This project aims to transform a former office building, constructed in 1987 in La Celle-Saint-Cloud by architect Jacques Grellier, into a social residential complex of 69 apartments along with 1,400 m² of activity spaces. Facing the Château de la Seine Saint Cloud estate, the site benefits from an exceptional setting characterized by the natural hillside terrain.

The building, with a floor area of 5,400 m², is situated on a 6,182 m² plot and is ideally located near the city center and the train station, both within walking distance. 

Designed with a post-and-beam concrete structure, the building stands out with its six staggered floors and facades featuring precast concrete spandrels with an exposed aggregate finish.

The two lower levels, initially designated for parking and technical facilities, retain this function, while the four upper levels, previously used as offices, are converted to accommodate residential units. The lowest level (R0) houses technical spaces, 69 parking spaces, and accessible entrances for individuals with reduced mobility, providing direct connection to vertical circulation.

The R1 level, formerly divided between parking and offices, has been cleared of its initial functions to be dedicated to new activities. Pedestrian access is maintained and enhanced by adding a landscaped ramp, offering an easy pathway from the outside.

The upper floors (R2 to R5) have undergone partial structural transformation to meet residential program requirements. A new spatial configuration is achieved by modifying the central voids to expand patios and optimize apartment layouts. These patios, measuring 10.4 meters per side, play a key role in orienting cross-ventilated apartments and accommodating smaller units. The existing staircases, spacious and naturally lit, are preserved to encourage foot traffic, while an existing elevator shaft is also repurposed.

This renovation project, conducted in consultation with heritage authorities, demonstrates the feasibility of adapting a building to contemporary needs while preserving its distinctive architectural character. This approach balances conservation and change, highlighting the effectiveness and durability of the original design choices.