Abstract French economic expertise developed significantly during the interwar period when economic issues, and particularly those resulting directly from World War I, became the overriding concern for Europe's democracies. Before the end of World War II, three major institutes of conjuncture had been created, all of them driven by the need for economic policy indicators. ISRES was established in 1933 by Charles Rist, the Institut Français de la Conjoncture was founded in 1938 by Alfred Sauvy, and ISEA was founded in 1944 by François Perroux. Not surprisingly, all three were working on productivity measures. From 1936, debate was focused on the issue of the forty-hour week and then moved to the context of the arms race and the preparation for an inevitable war. The war period resulted in shortages that required planning of production; and in the postwar period the focus was on plans for the reconstruction of France and then Europe more generally. All these periods generated demand for differentiated economic expertise in productivity. In 1946, the first French National Accounts were published alongside the establishment of the Commissariat Général au Plan and INSEE, which resulted in another distinct period.