L’Atelier Senzu

Transformation of the former SNCF headquarters

Located in the heart of the Maine–Montparnasse district, 34 rue du Commandant René Mouchotte reflects the architectural and social changes of the past 80 years. From a post-war sorting centre to an office building, it bears witness to ongoing urban transformation. The current renovation seeks to balance architectural heritage with contemporary challenges through an environmental, social, and urban approach. This creative reinterpretation aims to reconnect past, present, and future, while strengthening the building’s integration into the Parisian urban fabric.

Built in 1963 by Louis Arretche, the former postal sorting centre represents the excellence of modern French engineering, with its post-tensioned concrete slabs and layered organisation. A landmark of post-war infrastructure, the building stands out for its slender structure and innovative frames. The renovation aims to reunify the hotel and office parts through a renewed façade that highlights this unique structure. The project rethinks the building’s architectural expression, introducing a light and efficient envelope that remains faithful to its original heritage.

The renovation project restores clarity and value to the building’s original structure. The Agora, located on the fifth floor, showcases the historic frames and creates a functional space rich in character and history. Office spaces are inserted within the existing column-and-beam grid of the base, preserving its architectural identity while limiting demolition. The deeper floor plates are opened up with planted terraces, offering generous outdoor spaces that strengthen the connection to the city and provide a pleasant, balanced working environment.

The project reimagines an office building by offering adaptable and varied workspaces, including open-plan areas, modular offices, and outdoor spaces. By enhancing the existing structure and using a 1.35-metre grid, it creates large, flexible floor plates that support innovation and collaboration. Side circulation cores free up the central areas, allowing full spatial flexibility. Thermal comfort, acoustics, air quality, and natural light are central to the design, ensuring well-being and efficiency for both present and future users.

The project improves interior comfort by carefully balancing light, air, temperature, and acoustics. A redesigned façade maximises natural daylight through appropriate glazing and effective solar protection. Air quality is enhanced by integrating operable windows across 50% of the façade, safely protected. Active and passive thermal strategies provide individual comfort, while modular acoustic solutions and sound-absorbing materials create calm, adaptable workspaces suited to users’ needs.