ENSA Paris-Val de Seine Conférence


The idea of “Almost finished buildings” is that on completion they can still be transformed. It does not mean they should be left this way.

 It is more a question of meeting new material-saving and sound-proofing requirements as we build, to avoid having to rebuild every time and to have to redevelop everything when our aim is to rethink or make the city denser.

 Occasional changes are made possible by implementing additions drawn from geometries and media designed for this purpose.

 It is important to learn how to consume less (or better) and also to learn how to build less (or better). This amounts to creating a new aesthetic.

I could have spent all of this presentation talking about all my projects. However, I decided it would be better to present the activist vision of my work as an architect and through this, to elaborate on the more important projects of my career.  

I believe it is important that architects should recommit to this field of study and become civically involved in the protection of our urban environment, making it a healthy, aesthetic space.

As a background to these comments, let us say that the current ecological situation has completely changed our relationship with the world:

  • On the one hand, the number of virtual discussions and the frequency with which we travel has grown considerably with massive hyper-communication, closely linked to the Internet.
  • On the other, because we have gone from a sedentary society to a nomadic society and we have not yet adapted to the disruption that this has caused. A recent report submits that more than a billion people will travel by road in the years to come, due to climate change (climatic refugees for more than half of them) or politics.
  • Lastly, the population on Earth is growing without slowing down noticeably. We now consume a great deal more each year than the Earth’s natural resources can produce.

In the light of these reliable scientific observations and by standing back from a stagnating political debate, there are two not necessarily opposite, but complementary stances we can have.

1) On the one hand, we can act to save our natural spaces, by protecting housing blocks from the ravages of pollution and massive destruction resulting from land development pressure. But for how long?

2/ On the other hand, we can think more fundamentally about how we go about building the city of the future to make it more suitable and open to future developments.  We can act on our cities as new dense, contained and tidier living spaces.

So, what I am suggesting today is only the beginnings of a response, confined solely to the field of construction, for which architects can provide responsible solutions.

My presentation refers to an ever-changing city full of buildings that I decided should be “almost finished”.

The RBR 2020-RBR 2050 group

I have been contributing to the RBR 2020-2050 panel, since 2010. This is a committee run by Philippe Pelletier, appointed by the Ministry of Ecology, Energy and Territorial Cohesion. The purpose of this group is to propose solutions to make buildings more environmentally friendly and to greatly improve the way in which energy consumption is managed today in France. We want to bring the climate into the spotlight and favour public awareness so as to be able to change things in the near future.

“In some ways, to emerge from the globalization of thermal regulations that are identical throughout France, even though the climate varies a great deal between the north and the south”.  

The representatives of this group are public and private stakeholders. La poste, EDF, the CSTB (Scientific and Technical Centre for Building) for the public sector. BOUYGUES, Crédit Agricole bank and other property developers for the private sector. They are all stakeholders and major decision-makers in the construction industry in France.

In connection with this workgroup, I wrote a paper, in early 2018, on the modern, flexible city, the title of which was: EMBARQUEMENT IMMEDIAT (IMMEDIATE BOARDING)

1/ Zero Carbon / building constructions emitting less carbon and protecting the biodiversity of our land.  

2/ Reversible design of spaces / It should be our priority to leave everything open at the city level and to propose spaces of an “available” nature that can be adapted, in real time, to changes in people’s requirements. We also need to work as closely as possible on increasingly shorter economic cycles, to avoid damage to the land from rapidly obsolete single-purpose buildings.

3/ Three Scales / You can only act meaningfully on an environment if you pay close attention to the three major scales of urban planning: building, district, land.

Today, we are already sharing these three points with varying success. This is already considerable, but we must think of it as only a step towards the inclusion of all construction dimensions in a territorial or international study.

4/ Responsible Exchanges

We depend on the energy produced by other countries and on their requirements in energy produced in France.

 “But, is it normal that our ability to increase renewable energy decisively, should depend on the decline of coal in Germany? We are late in developing clean energies, such as onshore and wind turbines and hydro power, solar power, methanization or wood for fuel, depending on the regions in which they are developed.”

What is more and paradoxically, France has a wide variety of natural resources:  in the west: wind, in the north: rain, in the south, sun and in the east: fresh water.

We must therefore favour exchanges by acting on all the parameters of sustainable urbanization, linked with other urbanization projects to encourage competition and interregional support. Since it is by using our natural resources better and by placing them on responsible exchange lines that we can introduce effective measures that stem from a French model. This model would emerge from the ability to reorganize consumption and increase the energy independence of regions through intelligent exchanges between them and even as far as bordering countries.

5/ THE IDEE (Institute for the Development of an Evolving Environment)

To act meaningfully and develop this exchange, 4 Institutes were created. Fostering the development of an Evolving Environment (IDEE), they are divided among 4 climatic regions. These will be the institutes that will centralize the regional data and favour types of architecture and construction best suited to the specific climatic and industrial features of the regions in question.

This data would remain available to chosen members in different professional and academic branches: planning, environment, politics, landscapes, economy, energy, sciences, landscape and architecture philosophy. It would provide mayors, local and regional authorities, with objective, critical and constructive proposals.

Example: these institutes would be able to absorb all the creativity of architecture schools giving it back to the community, in a way influenced by the laws or by measures of common sense taken at all levels of the decision to build. 

Zero Carbon

In 2008, I was the first winner of the competition launched by EDF to address the LOW CARBON issue. This distinction changed a lot in the way I was seen in relation to my projects from then on.

The issue was the following: “How can you successfully reduce the impact of carbon emissions produced by buildings in the atmosphere?”

We know that the construction of buildings throughout the world contributes to 40% of the C0² emissions in the atmosphere. However, we are told that such massive carbon emissions contribute to the greenhouse effect and to rising average temperatures on the earth’s surface.

The competition focussed on proposing a new type of low-carbon emission building, in the hope of developing construction parameters responsibly.

My proposal focussed on four points:

1/ The pure form of carbon is the diamond and the impure form is carbon dioxide. I used the diamond shape and translated it into a visual project for the architectural identity of a low-carbon emission building.

2/ I brought the idea of the “draught” up to date, this simple natural form of ventilation.

The building is located in the south of France, in Montpellier. It is not very thick. I installed large openings on the south and small openings on the north. In summer, the thermal difference between the façade in the sun and the one on the north creates beneficial air movements that provide the upper floors with their own cooling, without having to add any energy consuming technique.

3/ What is more, I included the results of a study of a team at the University of Tokyo, led by Dr Hideki Koyanaka, by building manganese dioxide trays into my façades. He demonstrated that manganese dioxide acts as a catalyst, through the combined action of water and sun, resulting in artificial photosynthesis. This is how the building circulates oxygen, instead of emitting carbon.

4/ Every material in this construction was selected for its carbon footprint, by retaining the least energy-consuming in their manufacture, maintenance and recycling. Full study of the life cycle of materials

We are in an intermediary period in which “the control of carbon emissions into the atmosphere” is far from a foregone conclusion. However, taking this factor into account in our thoughts on all constructions in the future could be decisive. Of course, forthcoming regulations will aim for zero carbon emissions for all constructions.

Space Reversibility

I believe reversibility to be a good starting point in a new economy developed to build better constructions for longer, and to preserve quality and “an open transformable nature”.

The aim was to add the advantages and distinctive features of structures leading to the construction of office buildings, housing, hotels or residences, and produce a common base from the outcome that can be used as a guide. Housing, for example, would benefit from a greater height (quality of space), and offices would be able to rely on peripheral access balconies (maintenance) or terraces.

In 2017, I registered the IDI, Immeuble à Destination Indéterminée (Open Building) seal with ICADE.

And I illustrated this point more exactly with the presentation of the Black Swan buildings in Strasbourg, which, at the time of the competition, was a theoretical and prospective project and now shows that the goals have been met.

Simultaneousness and Complementarity of the Three Scales

The various projects I will show you examine the complementarity of the three scales of the city: the building, district and land.

Controlling carbon emissions on a building scale requires an extension beyond the district towards the land through anticipating requirements and leaving nothing set in stone. We think of the land as a grid of available spaces adapting to each period of time undergone.


So, three buildings which include and illustrate what I have to say in the first three points of IMMEDIATE BOARDING

These three projects are completed or in the process of completion:

1/ Les black swans as a new “completed” model of space reversibility.

2/ Les Dunes, a landscape building, a space installation of new office behaviour, at a time in which hyper-communication suggests (or demands) new working relationships. A landscape building that embodies the complementarity of scales between a building, district and land.

3/ Place de la Porte d’Auteuil, such as the pooling of design and production resources to achieve greater quality, rationality, scalability and better aesthetic creativity, within a more global context of a general passive and low-carbon emitting predisposition.


Les Black Swans is basically a virtuous project, since it rebuilds the city on the city, reconverting a former industrial site into a new district of the city centre, located very near the Strasbourg Cathedral…

Built in Strasbourg, it represents a 30,000-metre squared piece of the city.. The project will be completed in January 2019.

The public and private competition launched in 2012 was a joint operation led by the city of Strasbourg and ICADE.  In my opinion, this is the main reason for the success of the project. All through the development of the project, the city has kept a hand on the territorial issues, developed the economic connection between the centre of Strasbourg and the neighbouring city of Kiel, while ICADE was responsible for the construction of quality and, if possible, innovative buildings.

The project connects the passageway between the Malraux Peninsula, the former industrial site, and the Danube district, the new eco-district. Instead of piling up architectural accomplishments which would have expressed the diversity of the project programmes (but which would have prevented any later development of the buildings), I preferred to implement a moderate homogeneous structure that could be adapted to all the constraints and the changing projects of the district that seems to be changing overnight.

With the North-South axis, the project has revived the link between the centre of Strasbourg and the Neudorf district that ended with the industrial activity.

On the east to west axis, the project is installed like an urban stitch between the centre of Strasbourg and the economic development highway to the city of KIEL, in Germany.

This new district is well served and links the land at all points, near and far, through clean public transport, such as the tram line. This urban layout fosters the growth of shops and services associated with this mixed project.

This is a mixed-programme project for student accommodation, private apartments, apartments with services, a luxury hotel, offices and shops.

If we refer to these buildings as “almost finished”, this is because they allow several types of changes. What is more, between the competition and the buildings’ construction, over 50% of the programme area has been modified.

Characteristics of almost finished buildings

These buildings feature:

  • A unique layout for all the programmes allowing the programmes to be adapted to all the project data and to offer a much cheaper constructive system than a building project with diverse purposes, since it is the same no matter what uses are required.
  • The vertical service cores are located at the centre of the building and the façades are load-bearing, which means that the interior divisions can be changed without the slightest constructive difficulty.
  • The access balconies around the building provide confidential use of the areas developed for both offices and housing.
  • Access balconies in addition to sunscreens and (finely open worked) guard rails help preserve the architectural integrity of the building in relation to public spaces, whatever use is made of the domestic spaces.

The plans of the three buildings in their final form, which saw a change of over 50% between the competition and the construction. You can see an approximation of the three towers offset from each other so as not to interrupt the view or the amount of sunshine each of them receives.

Reversibility between the occupation of an office and housing was anticipated to make it possible at a lower construction cost. This forward planning was made possible by three main provisions:

  • Vertical cores designed with protective measures that are adapted to specific regulations for both housing and offices.
  • Office access balconies, which become balconies for housing, without making any changes to the exterior façade.
  • Heights compatible with a variety of uses and plan modifications that are achieved by moving partitions and not walls. Economic measures. Modifications are also made possible, perpendicular to the ceilings, and the size of the service areas, such as for the secondary networks, is not affected.

Reversibility increases the building’s rental value lifespan, insofar as the use of the building can be adapted to requirements. This creates the intrinsic value of the building, that can be leveraged during construction.

A reversible building is a building that lasts a long time. To achieve this, constructive quality and sustainability must be an intrinsic part of the issue. It is a way for us architects to take back control and to seize the opportunity of using reversibility as a new starting place for design. It is an opportunity to take back control of the purpose of construction.

We are part of an industrial process where the good reasons for doing things and aesthetic choices are at a crossroads between architectural identity linked to context, obvious and urgent climate resolutions, and of the effort to create buildings that last.

  • Flawless workmanship is an integral part of the constructive details (down to the nuts and bolts) of each of the panels.
  • The envelope and its outer structure are made of aluminium and do not require any particular form of maintenance.
  • The sunscreens are mobile allowing the adjustment of the amount of sunshine in summer and in winter, matching buyer or tenant requirements.
  • The exterior insulation and the static width of the building contribute to the effective thermal inertia needed for the building.

All of these constructive measures contribute to the passive thermal quality of the building, designed to cater to the continental climate of Strasbourg. Cold in winter, warm in summer. Here we can see the access balconies, sunscreens, canopy and guardrail, which help adjust temperatures and prioritize space privacy in relation to the public space.

The ground floor is of double height, favouring a greater availability of commercial spaces and allowing a change of use. The availability constraint is a pretext for improving the quality of the ground floor spaces.

On the left we can see the different housing concourses that are double in height. At the centre, the photo of the three towers, now (being completed) and to the right of the initial drawing image. You can see that there is not a huge difference, even though the programme has changed by over 50%!              


This building remains linked to a generic process in its design and at the same time it is an answer to an industrial context throughout history and a romantic one through its poetic significance.  This is why it is method and goals can be duplicated on other sites, but that its shape cannot. Its substance and architectural identity are entirely connected to the lakes and to swans!

Hybridizations / Taking Things Further

The important thing these days is to propose buildings that are open to changes, transformations and even additions, despite looking as though they are complete. This will ensure that they continue to endure beyond their configuration on the day of their completion.

Hybridizations / Base

If we say that the buildings are “almost finished”, this means that we know they are fit to allow several types of developments and hybridization from the base.


These transformations can emerge inside or outside the construction. They can be specific or extensive, somewhere between a straightforward change of partition and a change of template.


Second project illustrating what I have said: Les Dunes

In 2017, I completed the headquarters of the Societe Generale bank, in Val de Fontenay, in the Paris region. The aim was to build a construction with a floor area of 100,000 m². The whole story of this project involved juxtaposing two parallel considerations:

On the one hand, we needed to create a coherent large-scale world, opening onto a questionable urban context. On the other, we needed to draw spaces addressing new work patterns, responding to all current and future configurations.

I preferred an incomplete composition with linear constructions, placed beside each other, which break clean when they come close to the plot boundaries, without any form of project other than opening up the site to the surrounding landscape.

It is a landscape building composed of constructions formed using three successive and parallel folds with planted valleys. Between these waves of concrete and wood, grows an herbarium; gardens creating a pleasantly calm area.

The gardens are positioned north to south. This provides luxuriant plants around patios receiving lots of sunshine.

The buildings are positioned east to west, which provides the workspaces with lots of light, whatever time of day it is.

The total plot area is 23,000 m² for 100,000 m² constructed. The challenge was to make this density a quality. So, I thought of folding the land, as you would compress a sheet towards the top, creating three waves that would hold the majority of the surface areas.

This landscape building has three big layers.

The upper layer has almost 75,000 m² of open areas and emerges above the ground. The spaces located in the superstructures are not like ordinary offices. Flex office work has changed everything. You now occupy space that is free. The idea of an office allocated to an individual is on its way out and architecture is reintroducing light and comfort to the workspace, making it user-friendly.

The intermediary layer on the ground floor, from west to east, with access to the RER (regional rail service), serves the different sections of the buildings connected two by two.

Les Dunes’ architecture fully allows and facilitates movement. The relationship between space and movement really mean something. Although difficult to take in in one glance, because the room is so big, every day the worker encounters a succession of transparent living sequences, small squares, and gardens.

The third lower layer, but on a level with the Avenue Delattre de Tassigny, serves the different sections of the buildings, from east to west. You will have realized that there are in all, two superimposed roads, one in the open and the other covered, serving all the buildings. The interior road is an occupied floor, hollowed out and lit by patios.

This lower layer houses nearly 15,000 m² of shared space (which are meeting spaces and work spaces with the feature of being able to adapt to all configurations), and a solution to the new more fragmented temporalities due to new work methods. These spaces comprise amphitheatres, restaurants, meeting rooms, relaxation areas.

Large openings and double-height spaces are connected by stairs. These rooms encourage connected uses between the two superimposed layers of the garden.

This project is original due to the representation of the visible relationship between the space and movements of 6,000 people in the buildings. This increases the number of opportunities of meeting each other. This helps humanize the managerial innovations connected with the introduction of digital technology in the workspace.







Here we have the reception pavilion which is at the site entrance from the top level.

Landscape extends in horizontal perspectives and disappears into the garden hollows. The geometric organization of the ensemble does not preclude the visual organization the spaces. Paradoxically, the breathing spaces delimited by the patios offer a wide variety of viewpoints which contribute to the interweaving of two scales.

A subtle layout is achieved through the contrast between the large scale of the buildings (about 160 metres long) and the (relative) small-scale of the patios (which are about 10 m wide by 50 m long). The buildings of the superstructure frame the view of the distant landscape, naturally drawing the large scale.

The patios create more intimate scales, making all the shared spaces bright and comfortable. They help contribute to the continuation of all the headquarters activities outdoors.

The workspaces are intrinsically linked with the adoption of digital technology. Due to this digital choice, the idea is to be able to encourage work over a more extended lapse of time, intersecting times of highly focussed work with relaxation times.

The purpose of the spaces is constantly changing. It also involves creating a situation that allows an unbroken drift between work and complementary activities.

Each space can be adapted to different layouts thanks to its ergonomics. As for example, here, with amphitheatres that break with the traditional layouts of such spaces, with the aim of increasing the space frequency and opening up its use.

Architecture adapted to the digital revolution. To achieve this, we had to create atmospheres conducive to mobility, meeting people and interaction. The interior fittings contribute to diverse uses over the length of a day or a week or even in the longer term.

For the gardens, I worked with Pascal Cribier, for the interior architecture and furniture, with Christophe Pillet, and for the signage, with Rudie Baur.










Détail Façade

Les façades trouvent une interface inédite avec l’intérieur, lui-même modifié par l’intrusion d’un esprit né du numérique. Nos comportements, à travers nos façons de travailler, sont devenus évidemment différents. Avec l’informatique, nos besoins propres au confort ou à l’ergonomie se sont accrus. La lumière doit être abondante et mesurée, tout à la fois.

Détail Façade

Les lames extérieures en bois sont des brise-soleils verticaux. Les façades sont orientées prioritairement est-ouest. Ces lames verticales viennent atténuer la lumière directe entrant dans les bureaux. Le clos couvert marque une certaine brillance. Il est tout en aluminium. Et c’est ce décalage entre ces deux matières (entre la brillance de l’aluminium et la matité des lames de bois), qui crée l’épaisseur de la façade.

Détail Façade balcon

Les Dunes forment un paysage ondoyant et réglé. Le bois structure son image.

Le bois est la matière générique des immeubles. Il tisse le lien entre les jardins bas et les jardins haut. La répétitivité des détails constructifs contribue à la maitrise des coûts. Mais au-delà de la question du coût on vise la poésie de l’espace à travers celle de l’écriture

Un ordonnancement subtil peut s’installer entre les différentes pièces de la façade. Chacune des pièces a son dessin spécifique, comme ici les balcons d’étage.

Façade Detail

The façades have a unique interface with the interior, itself modified by the intrusion of a digitally inspired spirit. Our behaviour, through our work methods, has naturally changed. With computers, our need for personal comfort and ergonomics has increased. We need plenty of moderate light.

Façade Detail

The outer wooden louvres act as vertical sunscreens. The façades face, for the most part, east to west. These vertical louvres soften the direct light entering the offices. The envelope has a sheen to it. It is all aluminium. The difference between these two materials (shiny aspect of the aluminium and matt aspect of the wood) is what creates the depth of the façade.

Balcony Façade Detail

Les Dunes create a regular undulating landscape. The wood structures its image.

The wood is the generic material of the buildings. It creates a link between the bottom gardens and the top gardens. The repetitiveness of the constructive details contributes to cost control. However, beyond the question of cost we aimed to create poetry in this space through its representation.

A subtle layout can be introduced between the different parts of the façade. Each of these parts has its own specific design, as here with the upper balconies.

Façade Detail, Base of the Façade

Here also, the detail of the base of the façade that creates a junction with the ground, light, and water run-off. But each of these details remains in an identical assembly line. As if they stemmed from the same material to start with.

The wood used is reconstructed from wood that has already had a first life. It is a wood paste, made without recourse to oil-based products, assembled around a finely micro-scratched aluminium profile for good adhesion. I was able to combine 47 m long elements using this technique. This is the first time that this has been done in Europe, but this material has been used for more than 30 years in Japan. It is a material that stands the test of time and does not require any maintenance.

We could refer to recycled ecology here; of a recyclable recycled product.

To take things further

I spoke of landscape, of movement and flexibility. That is just what digital configurations involve, making movement easier and fully visible, ensuring that people’s eyes meet, that they also meet, and making responses more meaningful.

Taking Things Further

Rather than concluding with a finished project, I preferred to set up a grid of available spaces on site, physically concentrated in the buildings characterizing a constantly evolving landscape. Architectural identity, movement, mobility as a vector of communication, transformation and adaptability are part of the DNA of this landscape building. This grid of space available is completely flexible. It allows change and anticipates developments.


The Auteuil project in the 16th arrondissement of Paris is thought of by the public as a protected space where the upper middle-class socialize among themselves. It is clear that the percentage of social housing is low: 2.5%. The project that I am going to show you proposes to build 200 apartments for first-time buyers and 200 social housing units, side-by-side. Thus, the social housing represents 50% of the whole project. This might explain the lengthy period required to reach the end of this project. The project will be completed late 2018, although it began in 2008. It took us 10 years to win people over and build this challenge launched by the city.

This project is a really distinct project as far as my work is concerned: it is a homogeneous programme. 400 apartments needed to be built. However, it is distinctive in that four architects worked on it and not just one. Three well-known architects who worked alongside me to develop a coherent proposal within a joint presentation. These architects were Francis Soler, Rudy Ricciotti and Finn Geipel. As for me, I took on the difficult but fascinating role of the group’s appointed architect.

Another distinctive feature was that this project of 400 apartments was to be commissioned by two clients: Paris Habitat for the social housing and Altarea Cogedim for the first-time buyer housing. This project will be completed January 2019.

It is a project that suggests an alternative to the road centrality of Porte d’Auteuil, by proposing pedestrian centrality. However, it is primarily a garden that continues all the spaces left through the abandonment of the small circle line trains to the Gare d’Auteuil railway station. The idea was to create a generously planted inhabited park from this disused land, instead of continuing a fabric already completed with façade returns facing south.

The aim was to focus effectively on structural excellence in relation to sustainable development.

The project is listed in the Climate Change Plan (Paris city energy regulation and aims to be low carbon emission). To achieve this, we just needed to distance the buildings from each other by bringing them closer at their corners to bring sun into the gardens and into the interior spaces of the apartments and thus provide distant views through arranging their perspectives.

The aim was to build a sweeping park, so that everyone could enjoy the cool effect of the trees, as well as their foliage and canopies.

The small circle line has now had its ironwork removed, creating an opening in the urban fabric, colonized by spontaneous vegetation. So, the project was to continue this plant interpretation on a green corridor, which recalled the railway track leading to the Auteuil railway station.

Louis BENECH designed this green corridor. He did not wish to design and separate the mineral paths from the planting. He installed a mineral layout to allow arbitrary plantings. This layout is geometric, laid flat on the ground, from the façade of the building that I designed.

All the features of this urban feature weave in complementary materials and subtle geometries. The architects and landscape architect chose to work with each other and also decided to work with almost one material spreading across the ground in a multitude of small variations. This project works in counter rhythm to some recent projects, built with a lot of juxtapositions and architectural exploits that are very frequently overstated and express no fundamental collective thinking that would justify their existence.

The four architects showed, on the same plot, how rented and bought apartments could cohabit, without any specific downgrading distinction between social and first-time buyer housing.  

What was the method used to achieve this?

The idea of a using a component cooperative and pooled constructive systems. Identical constructive systems were used for the three buildings. The same millwork and the mass effect helped bring down construction prices. This allowed innovations, such as the use of folding doors and windows in the four buildings. The visible material aspects, based on pleated, perforated aluminium, aluminium oxide base, were shared and used by each of us to create a joint work.

What is more, the project reveals careful detail in creating a good depth and lighting ratio, so that each building has efficient thermal inertia. The apartments are either floor-through or have a dual aspect. This favours good natural ventilation. All the apartments have a balcony or terrace.


The whole of the building project creates a work that is coherent as a whole. One might have thought that four architects would have resulted in four completely different buildings.

In the end, although they do not look completely the same, they are not completely different either.

The pooled components were used in a different way by each architect. In their own way, each of them contributed to this urban feature, which although hybridization, stands out for its manifest visual coherence, a contemporary and uncompromising transposition of the Haussmannian City.



The choice of projects, of a domestic nature (offices, housing, hotels and others) is voluntary. Domestic projects represent over 80% of a city’s construction.

And it is more efficient (and of a more structuring nature) for architects who are interested in ecology to focus on doing this through domestic spaces that consume fewer polluting materials (philharmonic hall or museum), instead of through the construction of large public facilities that are increasingly rare and less frequent than housing projects.

All this structuring research for the future of our cities and our regions, in no way prevents us from contributing to new aesthetic designs. We can develop environmental authenticity without it being mundane.

The question of flexibility is a recurrent issue that we now see as an important avenue in planning the way in which cities develop.

The Munich-based architect Otto Steidl used the precast beams of the concrete industry, which enabled him to create an arbitrary aesthetic, while aiming to reduce project costs.

He created a new aesthetic.

My recent constructions are characterized by my desire to ensure that the construction was not static. The mixture of programs, their ability to evolve over time and adapt to changes in use, contribute to reducing carbon emissions in the atmosphere and limit city sprawl.


Another way of considering “IMMEDIATE BOARDING” and to think responsibly, is by looking ahead to a building’s new life, rather than starting over. Building over already existing buildings is to act in favour of a responsible economy.

LE GRAND NANCY THERMAL will be the largest spa centre in the East, by the number of 17,000 spa-cure takers expected per year alone. This spa centre is located near the railway station.

The project is led by Métropole LORRAINE. The site regeneration will improve its attractiveness.

The architect Louis LANTERNIER built the NANCY thermal baths when he discovered a borehole in 1914 with water in the region of 36° C. These were closed in 1917 on his death. The thermal baths are an unfinished construction that now needs to be completed.

But how could this beautiful incomplete symmetry be completed?

 There were two solutions for this:

1/Either to build a replica of the already existing, with the obvious risk of creating a less well-made building, considering the loss of skills in the complexities of stonework.

2/Or by trying to hybridize the styles.

I was more tempted by hybridizing styles with a new interpretation of the historical façade.  It is the juxtaposition of a contemporary representation that reinvents our perception of it. So, I adjoined an inhabited volume of the same size symmetrically. It is manifestly the opposite of the original, both in terms of colour (black for white) and façade lines (horizontals for verticals).

It is organized in a similar layout (circular shape centred in a square shape) surmounted by a dome visible from a distance.

The historical building’s stone concrete and the metal used for the contemporary building are the new materials of this distinct hybridization. They now form an architectural ensemble.

By building the city on the city, is this not an opportunity to repair the mistakes of the past? In the 1970s, the building as an entity was rejected and reduced to a vulgar fixture left to fall into disuse. A new sports and leisure centre was situated between the façade of the thermal baths’ entrance and took up position between the district and the Jardin Sainte-Marie (park).

Can you repair the mistakes of the past?

The sports and leisure centre was positioned in the right spot, south of the plot. So we can still have the historical entrance to the thermal baths.

Rebuilding the city on the city is also making use of past investments to achieve something bigger, while highlighting the already existing buildings.

The existing thermal baths were restored and a treatment centre was added, in addition to an apartment hotel for spa-cure takers.

The Olympic swimming pool was restored and fitness rooms were added. The sports and leisure spaces were repositioned in the right place.

A hotel and restaurant were added taking into consideration the influence such a spa centre is likely to have (unique in France and in Germany).

In size, Le Grand Nancy Thermal is worthy of the Caracalla thermal baths. The Parc Sainte Marie unfolds on 70,000 m², while the surface area of the buildings is 30,000 m².   

By hybridizing and confronting styles, this has strengthened the power of the compact nature of the building. The composite and hybrid image looks like a large black and white tablet, laid on the green of a very simply designed park.

The whole of the project exhibits old and new features alike.

The spa park is big and free of any construction or any vehicle interrupting the extensive perspective leading towards Parc Sainte-Marie.

A continuous carpet of plants dotted with a few wood copses, in the same species as those of the Parc Sainte-Marie, is situated between the spa and the hotel.

History resumes where it left off in 1917 


Paris city’s ESPCI Higher Institute of Physics and Industrial Chemistry is in keeping with an international scientific goal.

The ESPCI is located on the Montagne Sainte-Geneviève (hill), a historical site favoured for research.

The Institute has left its own mark on history through the quality of its research and its major discoveries.

The main feature of this establishment is that it forms a building block of successive extensions. At the time of the competition, I proposed that it should be given general coherence through aligning it with the streets which form the block and bringing back the line on itself to close it off.

The challenge of the international competition, launched by the city of Paris, was double:

1/ It required eventually doubling the institute’s surface area. This would solve its growing needs and give it spaces worthy of its international prestige.

  2/ It also required rendering the premises modifiable and adaptable to changing requirements.

To meet this challenge, the question of whether the existing spaces should be preserved had to be asked. Should we leave the existing building as it was and repair it, avoiding a natural extension of the Institute?


Or should we accept preserving only the most interesting part of its history (i.e. the historic façade of the 1930s) as sound memory base? This memory base would be completed by a regular development of a generically covered portal frame. This in order to design buildings in which all the spaces can be modified to meet the researchers’ requirements.







The Lycée Hôtelier de Guyancourt is a building dating back to the 1980s, which I had to re-develop within a few years.

It is the largest catering school in France, for the number of its beginners’, application and patisserie kitchens. Above these are the boarding facilities and classrooms.

Although the building is relatively recent, it was on the decline due to being excessively complex to operate and a bad image.

The physical power of the existing building is striking. The intervention agreed to opt to extend it rather than contract it. The energy of the building served to revitalize the catering school.

There was a threefold challenge:

1/ We had to restore peaceful urban visibility. The building’s parasitic features were removed by an outer covering.  

2/We had to restore access visibility and simplify the way it is used: a large square crosses the school from one side to the other giving it an urban foothold and distributing all the units of the programme.

3/ We had to make it more educational, and more indicative of the catering schools’ reputation: an aluminium technical layer establishes all the kitchens on a single floor and returns proper order to the technical constraints to reduce operational costs and provide an educational tool representing the demanding level of culinary art through the legibility of the development.