The structure housing the Ferembal offices in Nancy was built by the Ateliers Jean Prouvé in 1948. The bent steel frame comprises five axial portal frames set on a pressed steel floor and is held together by ridge beams which support the purlins and aluminum roofing slabs. The prefabricated double-sided wood panels used for the facades slot together interchangeably, which is also the case for the winter garden and the internal partition walls. After the war Ferembal CEO Pierre Bindschedler was a member of the French government team in the Saar, and was able to back Prouvé’s plans for involvement in large-scale creation of housing and public facilities via mass production of the steel components for the portal frame system. But Prouvé was ahead of his time, and only a handful of prototypes were ever made. Rescued from the demolition of the Ferembal site in 1983, this striking example is another eloquent illustration of the approach’s technical and functional virtues as well as its adaptability. At the request of the Galerie Patrick Seguin, architect Jean Nouvel undertook a thorough “adaptation” of the Prouvé building, demonstrating the enduring relevance of the method. Originally a second-floor structure on a masonry base, the metal building has been given a new configuration as a detached house. Drawing on today’s technical resources, Jean Nouvel points up and skillfully exploits the structure’s inherent mobility by systematizing its modularity with piers of stackable Ductal blocks, a floor of removable slabs, etc. The design of a new staircase in response to the decrease in the building’s height above ground is perfectly attuned to Prouvé’s underlying constructional logic.