This retirement home is located on the heights of Riedisheim (a suburb of Mulhouse), in a residential neighborhood. The conjunction of geophysical and regulatory constraints rendered this plot of land difficult to build upon : its elongated form, its gradient exceeding 10%, and the very restrictive POS regulations applicable to it were a priori incompatible with the size and demands of the project. These conditions led us to develop the entire project within a construction adopted to the form and constraints of the land. The building unfolds in length from east to west, while its height, made of up of four trays slightly shifting away from one another, follows the natural slope. The roofs, visible from the principal access road located at the top of the plot, are all planted, which helped dampen the impact of construction in the neighborhood.