The monumental objects of the Raspail tower and the Spinoza housing project are the result of Gailhoustet’s earliest experimentation with the habitat. Their organization in duplexes bestows some of the characteristics of the individual house on apartment living. Profoundly influenced by the building composed of staggered terraces on the Avenue Casanova in Ivry-sur-Seine built by Jean Renaudie in 1972, Gailhoustet began to explore new areas of research. One of the earliest fruits of her thinking, she started designing this little-known neighborhood of the Place de la Fontaine in Villejuif in 1978 and it was completed in 1981. Financed by the town’s Public Housing Office, this complex located near the town hall, comprises 35 duplex public housing units as well as Social Security offices. Developed horizontally this time, the construction is punctuated by terraces and patios and represents an alternative solution to the banal and persistent urban forms of the suburbs, which are after all towers and single-family homes. Its originality stands out when it is compared with the bar-shaped block of housing units proposed at the same time by the architect Chemetov of the AUA. Unlike the tower, the horizontal plane is not a frozen object. Here, Gailhoustet drew inspiration from heterogeneous examples, such as the clusters of dwellings of the Siedlung Halen in Basel (Atelier 5, 1961) and the multifunction megastructure of the civic center of Cumbernauld in Scotland (Wilson, Copcutt, 1962). Her plan is the result of adding together modules positioned along strips. These modules are defined by the housing units equipped with patios and terraces, and by their crosswalls, and they are designed to be able to evolve and be expanded. As such, the completion of this project in Villejuif is only a part of a much larger project envisaged at the start. It served as an extremely convincing prototype, whose underlying principles would be reused in the Marat project in Ivry-sur-Seine and the tranche 8 of the La Maladrerie district in Aubervilliers.