The property complex at 32 rue de Trévise in the 9th arrondissement of Paris is made up of 3 buildings, including a private mansion classified as a historic monument and a protected green space in the heart of the block. 

The Hôtel de Bony, at the heart of this complex, was built in 1826 as a "romantic folie", then became a bourgeois mansion in the 1850s, before being classified as a historical monument in 1976 and restored in the 1980s. The PIERRE BORTOLUSSI agency acts as heritage architect on the listed building.

The restructuring project designed by CALQ aims to transform the two office buildings and the listed private mansion into a high-end tertiary real estate complex, which is part of a sustainable development and recycling approach for the existing buildings.

The concrete façades will be retained, the joinery replaced and the thermal insulation improved. The underground car park, created under the garden in the 1980s, will be transformed into a business centre to provide real communication between the three buildings on the site. Glass floors will bring natural light into this new central space.

The protected green space on the roof of the car park, currently 13 steps down from Rue de Trévise, will be completely remodelled and raised to become accessible from Rue de Trévise on one level. The thickness of the garden's soil will be increased and open spaces will be created to enrich the site's vegetation, plant trees for medium development and promote the attractiveness of biodiversity. The flat roof of the building at the bottom of the plot will be planted. Insect hotels and bird nesting boxes will be set up on the site.

The project aims at BREEAM Very Good certification.