What is it that you find particularly interesting about conversion projects, like Station F?

I like being able to design architecture in a manner that enhances the existing elements, and to make them blend into the site and bring it back to life, or at least to give it new life... In practical terms, that means keeping all or part of the edifice and adding on the contemporary sections that will accommodate new uses: I call this a ‘contemporary graft’. It could be clearly visible; or could be almost imperceptible. This type of project is always marvellous because it allows us to continue writing the ‘city story’ using elements taken from the past, the present, and the future... It contributes to producing the city identity, something people are attached to. It’s something that is shaped by the project and that shapes the project. Converting a heritage building has an influence on bringing the community together.

How can we add contemporary architectural value without losing the ambience of the converted building?

We always have to be very careful to respect the building itself. The first thing is to really get to know the building’s architectural identity, identify its intrinsic qualities; then, and most importantly, to make good use of these things and, above all, draw attention to them! Reveal its strength and beauty, while retaining its original character. That’s what has to guide you when you’re making choices like: What should we keep? What should we remove? What should we add to it? While I'm on this topic, it doesn't matter how old the building is, we must never forget that we live in the 2020s. We must avoid rehashing the past and avoid historical imitations at all costs! Graciously accept this coming together  this union  of two historical periods, and work with it. ‘The contemporary elements reveal and highlight the building’s past, in an interplay that brings out the best of both.’ Obviously, this play of contrasts, or alternatively ‘continuation’, has to be done carefully and with a light hand... The choice of materials is very important for this interplay of past and present. I’m not talking about architectural gestures now, but the functional aspects of the building. The work must revitalise the structure and prepare it for its new use, which means a new building programme with new spaces, improved circulation and equipment that meets modern building standards (insulation, safety, comfort, etc.). All of these building constraints  plus a veneer of creativity  bring the contemporary form into being. It is the fruit of this complicated process.

Why was the Halle Freyssinet conversion such an important project?

The building has remarkable architectural features, and its structural design includes the first known use of prestressed concrete. It’s a building that only narrowly escaped the worst. At one time there were plans to build a shopping centre there or transform it into a court of appeal. If that had happened, the building would have been lost; or at least, it would have lost its unique character and intrinsic qualities. Station F was a good choice for this site because it uses the full building footprint. The project is cleverly designed to slot nicely inside the building’s walls without having to change its appearance. The project leaves the vaulted concrete ceiling visible and gives visitors an open view all the way through the building. The good thing about the project is that it preserves the historic industrial features, which have been given pride of place rather than hidden.

How does this design suit the specific requirements of start-up companies?

The project revolves around start-ups, of course. We thought about how they operate  generally speaking  and how they might operate in this particular building, while keeping in mind that the space cannot be divided up endlessly with partitions. This is why we came up with the ‘village concept’. In other words, we have a single spatial and functional unit, at the centre is an area for relaxing that includes a kitchen; there are two small meeting rooms; a technical hub with stairs; restrooms and technical spaces; and two co-working areas seating up to 120 people. This layout divides the space without segregating it. We worked on this basic idea a lot. It makes everything more flexible, while also solving the building’s technical issues. We actually went to visit important actors from digital companies and start-ups seeking inspiration. For example, we visited NUMA, and The Family, which is a business incubator.

Interview by Jordi Patillon.

(c) Jean Grisoni