Following the decentralization of part of its services in the early 1980s, Électricité de France decided to relocate the Service Études et Projets Thermiques Et Nucléaires (research center for thermal and nuclear studies) from La Défense in Paris to Villeurbanne. Claude Parent, who had already worked with this state-owned company on nuclear power plant projects, was selected as the architect. The project did not go through the usual competitive process given the “complexity of the works,” but also and especially because of its strategic aspects. Parent worked with the architects René Gimbert and Jacques Vergely of Villeurbanne and the landscape architect Jérôme Vital-Durand of Lyon. The latter took charge of developing the main hall, which comprises terraces, plantings and circular ponds in an 800-m² area of green space. From the choice of the site all the way to the acceptance and sign off on the building, the architects followed each step of the construction process in close coordination with the client’s project management delegate, M. Maerten, deputy director of the S.E.P.T.E.N. Several projects were developed to meet the E.D.F. engineers’ requirements, most importantly to facilitate communication between the various departments. Behind the architectural part that was finally chosen hides the simplicity of the plan, an idea Claude Parent had been working on since the 1960s. The main building, square in plan, has a vast central courtyard (30 m x 27.5 m) under a glass roof. Inside this system, vertical circulation is via elevators and horizontal circulation, between the various floors, via ramps with a 5% incline. They enable one to move from the ground floor up to the fifth level without encountering a sharp break. The light penetrating from the glass roof is further enhanced by slits in three of the façades. Two other smaller buildings are attached to this cube in reinforced concrete and clad in polished granite.