ZUP was short for zone à urbaniser par priorité, a program of the French government to prioritize certain types of urban development. Max Stern, a colleague who had participated in the planning of Flaine and helped develop the program for the ZUP de Bayonne as head of the Bureau d’études et realizations urbaines (BERU), informed Breuer of the project to design a satellite town for 15,000 low income workers near Bayonne. Between 1963 and 1964, Breuer and his partner Robert Gatje designed a master plan for the new town incorporating high- and low-rise apartment buildings around a core of civic and cultural buildings. One of the most striking features of the plan was the serpentine line of 14-storey slab apartment buildings at the edge of the site. The town was a departure from traditional French architecture and urbanism proclaimed through its frank use of concrete construction, especially the modular pre-cast concrete panels used throughout. Breuer’s office built most of the town’s buildings but gradually lost control of the project with buildings by other architects added with little regard for Breuer’s master plan and rigorous aesthetic vision.