The extension of the Apprentice Formation Center is a compact and economic building. It achieves the composition of the complex of the Chambre des Métiers of the Val-de-Marne Departement, near Paris.
In a game of inversion, the new building backs its concrete facade and is based on a complex steel structure. The long span (20m) of the plumbers workshop is assured with full height beam that frames the second floor. The triangulations of these beams give the diamond shape of the upper level windows and the inclination of the zinc.