A ciel ouvert establishes links between different scales of spaces, programs and inhabitants, with the aim of conceiving a place to work, study and live. For this purpose the programme is fragmented into housing and office units which alternate in many combinations, taking the form of programmatic belts, basis for an urban architectural and landscape projet. These belts generate a soft infrastructure, which is superimposed on the existing high-speed infrastructure. The width of each belt defines a typology, which in turn leads to variations, producing a wide diversty of life and work styles.