The municipality of Perly-Certoux planned to build a complex of sheltered housing, social infrastructure and commercial and administrative spaces near the customs house, on the border between Switzerland and France. The architectural concept that won the tendering process proposed a building articulated around the customs house, which is a classified historical building.

The basement uses almost the entire lot and hosts a parking deck, part of which can be converted into a civil fallout shelter for 800 people. The basement also houses cellars and utility rooms. The ground floor is marked by the entrance hall, which is lit naturally by a skylight. This space connects the apartments, the commercial spaces and the restaurant. The upper floors are devoted to housing, and foot traffic revolves around the central atrium. The customs house was also restored and reinforced to be used as communal space.

The project included building a large basement near neighboring structures—buildings and roads. Its construction required excavating some 10,000 m³ (350,000 cu. ft.) and using excavation support measures. For example, soldier pile walls were built against roads and under the customs house, and soil-nail walls were built in less sensitive areas. These walls made it possible to limit displacements to less than 1 cm (7/16 in.) and to avoid damaging existing structures.

The building is characterized by cantilevered elements, including the dwellings above the main entrance, by walls that divert loads to the parking piers and by a central atrium with a skylight. All the structures were made of reinforced concrete, and the passage walls were made of exposed concrete. The walls were designed using the strut and tie method, and the overhang above the entrance is supported by four transverse walls that were prestressed at the top, directing the force to the entrance hall’s columns. The creation of the central atrium required creating large openings in the slabs of the upper floors. Specific constraints were analyzed by a finite element calculation.