Accessible via the Bouvets footbridge, Basalte marks a decisive development in the renewal of La Défense, scheduled for 2016. Like the Exaltis building in 2006, the 160-metre-long Basalte is part of a plan to reclaim and optimize land resources. Between the Granite tower and the Pacific footbridge, it spans one of the main access routes to the ring road.

Designed to accommodate 3,500 Société Générale traders, the building comprises five open-plan office floors, two technical levels and seven levels of underground parking.

From a technical point of view, the steel structures are dry-assembled, ideal on narrow sites, and are composed of truss-beams to free up floor space. On the south side, these beams rest on a metal mesh that strongly marks the building's presence.

Work on the building, designed by architect Jean Mas (Ateliers 234), began on July 21, 2008. The building is a technical feat due to its location, suspended above the RN 314.

A High Environmental Quality (HEQ) approach is being applied to its construction.

Together with the Chassagne, Alicante and Granite towers, this building forms a 245,000 m² real estate complex, with a workforce of around 16,000.

Les Ateliers 234 was born in 2005 from the merger of the agencies Bolze et Rodriguez-Pagès, Arene Et Edeikins and Mas et Roux. With over a hundred employees, this new agency has established itself as one of the leading players on the Parisian scene. Specializing in environmental quality, Ateliers 234 also works in urban planning and landscape design under the name Faubourg 234.

In 2009, they delivered one of the two office buildings that mark the Porte des Lilas in Paris, the other by Valode et Pistre. The agency, which is relatively young in structure but relies on collaborators who have been active since the 1980s, signed the Basalte building at La Défense.