The buildings of the cultural and community premises of Paris Diderot University fit into the undeveloped, southwest area of the Flour Market which was recently converted by Nicolas Michelin and Associates Agency. A break between the Flour Market and the new building is preserved. It respects the existing building and accentuates the slenderness of the tower. The two, independent buildings coexist completely. The signal-like extension stands out of its context by means of its evolving shape. It is a sensitive, delicate object, treated simply to avoid rivalry with the strong presence of the Flour Market. On the contrary it acts as a light, gravitational counterpoint. An architectural dialectic and emulation come into play much like a castle and its keep, both intrinsically inseparable.