Situated between the Croix de Chavaux and Montreuil Town Hall stations, these 16 passive social housing units slip into the dense and complex fabric of downtown Montreuil (93). The narrow and elongated plot of the dwellings testifies to the market gardening past of the city and the time of the walls with peaches. The first tour de force of the dwellings is to enlarge their narrow plot to make it a convivial space. An inner street, in the center of which is a plot, runs along the building from one end to the other and creates an inner urbanity that gives air accommodation. The apartments stretch out into a straight strip, the base of the first two levels of which is uniformly enveloped by a reflective material that multiplies the light in the garden. The second performance of the dwellings is environmentally friendly. The building reaches a passive level, despite an elongated little compact volume and housing exposed to the east and not to the south – privileged orientation to be heated naturally. It is the layout of internal volumes and the use of wood in structure and cladding that guarantee this excellent energy performance. Against all expectations, these dwellings illustrate perfectly how constraint can lead to an innovative project.