This project is part of the OnE project, which includes a comprehensive rehabilitation of the Eiffel

Tower site, stretching from the École Militaire to the Place du Trocadéro. The project involves the rehabilitation of an underground passage located beneath Avenue des États‐Unis, in the Trocadéro
Gardens, which previously served as a storage facility for the cleanliness services of the City of Paris.
The location has had multiple lives, bearing the marks of its history, as evidenced by the numerous flints inscribed with names, first names, and states of the United States, all dated between 1944 and 1945. The original structure was designed in the 1930s and is part of a set of bush‐hammered pink concrete constructions (Architect Roger Lardat, 1937) that are found on both sides of the Trocadéro Gardens. The project utilizes the typology of the passage to propose an outdoor and well‐ventilated space, adapted to its usage. The intervention is limited to the addition of a material, stainless steel, which constitutes the entirety of the intervention, thus making it readable; in contrast, the existing materials (flint walls, pink concrete) stand out and are highlighted by the treatment of artificial light. The entirety of the existing structure has undergone careful restoration: the glass domes required the re‐issue of glass blocks with specific dimensions and texture, the flints adorning the passages were reattached one by one, the degraded pink concrete underwent hydro‐blasting, followed by a purge consisting of partial demolition of the concrete and exposure of the existing reinforcements to allow new concrete to be poured, finished with sandblasting to unify everything.

As the project is located under a highly trafficked roadway where tour buses park, the significant stress on the expansion joints at the roadway level led us to opt for internal recovery of infiltrated water, from below. Internal gutters were designed in stainless steel and extended into soffits that conceal the grazing artificial lighting. On the facade, a sliding Corten steel grille, sculptural and incorporating seating conducive to waiting, closes the space.

Renovation of the Warsaw Fountain
Associated with the renovation of the East Tunnel, the renovation project of the Warsaw Fountain, located below the Trocadéro square, took place. It was also built in 1937 by architects Henri Expert,Paul Maître, and Adolphe Thiers.