Close to the Collines de l'Arche, designed by Jean-Pierre Buffi ten years earlier, the Triangle continues, in a way, the principle of contrasting the isolated buildings of La Défense with a more articulated organization. The goal: to develop a sense of urban fabric on the slab. In 1996, Jean-Pierre Buffi was tasked with determining the master plan for the neighborhood, formerly known as Triangle de la Folie.

The Triangle offices are housed in three interconnected buildings, each with a different shape. One faces the Faubourg de l'Arche, another square building is centered around a patio, while the last, shaped like a bow, echoes the sharp angles of the Collines. The complex is crossed by two streets. One connects the Westfield Cnit and the Palatin I building. The othere enjambe le boulevard circulaire pour déboucher sur l'esplanade du Faubourg.

Denis Valode (1946) and Jean Pistre (1951) founded their agency in 1977. Within 20 years, it became one of the largest in France. Its success was due in part to the reconstruction of the Lainé warehouses in Bordeaux and the construction of the L'Oréal factory in Aulnay-sous-Bois. Today, the two architects are particularly involved in the design of towers—in Saint-Denis, Lyon, Beijing, and Mumbai—and sustainable development. In La Défense, they are carrying out seven projects, including the Léonard de Vinci university center, Opus 12, and Engie B.