As early as the summer of 1940, the reconstruction of cities destroyed during the blitzkrieg began within the Délégation générale à l'équipement national and the Commissariat à la reconstruction immobilière, administrations created ad hoc by the Vichy government, based on a vigorous critique of the policies followed after the First World War.
Dominated by engineers, these sometimes overstaffed administrations were responsible for the plans drawn up in the field by architects deployed according to hierarchical procedures, the first of which were completed as early as 1941. Nationwide discussion and approval bodies, such as the Comité National de la Reconstruction (National Reconstruction Committee), were the scene of in-depth debates on the doctrine behind the plans and the relationship to be established between the restoration of historic buildings and modern construction.
At the same time, in-depth research was launched into the standardization of construction elements, standardization and the hypothesis of prefabrication systems, which came to fruition after the Liberation.
