To optimize its assets and bring together its administrative services on a single site, Sarcelles town council acquired the "Tour du Forum" office building, leased until then to a mutual group. Located in the Flanades district, this high-rise building is an ensemble of 16 levels consisting of four main blocks around a vertical distribution node set on a parking lot in the basement.

Delivered in 1972 by the architect Jacques Henri-Labourdette, a famous representative of the Modern Movement, this ensemble is representative of the creeds of an era. Forty years later, the building has had to evolve to meet its change of purpose in terms of functionality and technical and environmental efficiency.

The design proposal is to redevelop the forecourt around an extension on the ground floor of the building, on the north side. At the same level as the courtyard, this extension receives the busiest administrative services. This redevelopment is completed by work on the site boundaries: enhancements of the surrounding woodland to the north, and to the east, implementation of a screen of vegetation to manage the visual relationship with the "forum".

The creation of an enormous dual-aspect hall provides public access from Avenue du 8 mai 1945 and Boulevard Henri Poincaré. Linking these urban strucutres in this way manages the differences in level between the two streets.