This university centre is a place of shared and mutualised activities, meant to encourage exchanges between campus users : students, researchers, teachers and local employees. The building is an architectural symbol that prefigures the active and urban futures of Saclay's campus. The different activities are organised in a series of superimposed terraces that range from a public square to a wide roof-terrace dedicated to sports. A café, a university restaurant, a reception and entertainment area, fitness rooms and outdoor playgrounds are suspended vertically to provide, at every level, a panoramic view on the landscape of the plateau of Saclay. As they are visibly displayed on the exterior of the project, the activities themselves become the real facade of the building. A double monumental staircase, which serves as a central public space, visually and functionally articulates the various programs. This organization forges an open and flexible space, which operates 24 hours a day. All activites are accessible independently from the stair. On the scale of the district, a public square between the existing Engineering School and the future campus centre composes a new public space ideal for meetings and events, while serving all users of the community.