Like the Fiat Tower (formerly Areva), the Dexia Tower (renamed CBX) is the fruit of Franco-American collaboration. With its lower levels perched on stilts and its “plaza” - an open space at the foot of a tower - it is the most New York of the La Défense towers. Designed like the prow of a ship, it benefits from constant natural light. However, CBX retains a distinctive feature of the business district, namely the combination of a rectilinear and a curved facade.

Founded in 1976 by William Pedersen (1938), Eugene Kohn (1930) and Sheldon Fox (1930), Kohn Pedersen Fox Associates follows in the footsteps of its predecessor, Skidmore, Owing and Merrill. Specializing in office towers, the firm works all over the world. Since the 1990s, it has designed many iconic buildings, including the Adia Tower in Abu Dhabi and the Shanghai World Financial Center. In 2012, the agency completed the Pinnacle Tower in the heart of the City of London. In La Défense, it is involved in three projects: CBX, Logica and First.

SRA Architectes was founded in 1996 by Jean Rouit, Hervé Metge and Clémence Fiant-Saubot - daughter of Rouit's former employer, Roger Saubot. The firm quickly specialized in large-scale projects, working with some of the world's leading architects.
At La Défense, the firm teamed up with its American counterpart, Kohn Pedersen Fox, for the refurbishment of the Logica (former EDF-GDF tower) and First (former UAP tower) towers, as well as for the construction of the Dexia tower (now CBX), in 2005. SRA Architectes is also involved in projects for the Défense Plaza building, the Carpe Diem tower and the Phare tower (project abandoned in 2015).