The project involves the complete restructuring of the original building designed by Bernard-Henri Zehrfuss, currently serving as the headquarters of Crédit Mutuel, with a full renovation of the façade and all technical systems. The new program will provide 14,500 m² of renovated office space. This project was designed by LBBA - Lobjoy – Bouvier – Boisseau Architectes in collaboration with Legendre Construction (acting as lead contractor) within the framework of a competitive dialogue process organized by the client.

The architectural approach aims to transform the building while implementing climate transition strategies: the decision was made to renovate rather than demolish, the new façades are designed to be low-carbon, incorporating timber for the structural inertia of framed façades, and rooftop terraces are enhanced, planted, and made accessible, maximizing outdoor spaces at multiple levels while preventing impermeabilization.

The façade design features a timber grid curtain wall at the ground floor and a prefabricated timber-framed façade for the office floors. Some sections of the rear courtyard façade, which is south-facing, are equipped with projecting sunshades combined with an external thermal insulation (ETI) façade. Sunlight studies identified highly exposed zones without shading, leading to the development of customized sunshade overhangs for optimal solar protection. The framed façades are fitted with vertical brise-soleil, which serve primarily as an architectural feature and privacy screen, ensuring discretion while allowing for greater glazing than in the original design.

The new HVAC system eliminates parapet-mounted units, allowing for larger glazing heights and improving natural daylighting in the office spaces. Certain façade modules are equipped with large glazed openings behind accessible balconies, providing outdoor access in areas where no terraces are available.

All window units are designed to be operable, enabling natural ventilation and facilitating maintenance access. The numerous terraces at varying heights make the installation of maintenance gondolas challenging, further emphasizing the need for accessible windows.

The entire project is guided by a rational and pragmatic approach, leveraging the existing building’s structural assets, which include multiple south-facing terraces. The façades are designed in response to their specific orientation and use, ensuring occupant comfort, functionality, and climate resilience.