On the eve of the Second World War over one-third of the French labour force was employed in agriculture and yet France remained a net importer of agricultural products with an export cover of 35.2 per cent.1 Whether the low productivity of French agricultural labour was a cause or consequence of the restricted size of the industrial sector and of the decline of France as a world power in the nineteenth and twentieth centuries has long been a central issue of debate.2 Since 1892 when Jules Méline had responded to the threat posed to French producers in both industry and agriculture by increasing tariffs, French agriculture had demanded and received many and varied forms of protection.3 After the collapse of world food prices in 1929 these had included price supports and quantitative restrictions on imports as well as tariffs. However, to conclude that protectionism itself was responsible for the relative inefficiency of French agriculture would be to ignore the evidence of the period after 1945. Indeed, one of the most marked changes in the economy and society of postwar France has been the number of people leaving the land and the vast improvement in the productivity of those remaining on it. Between 1949 and 1962 the rural labour force declined by about 1.75 million; a fall of 31 per cent. In the 1950s the rate of increase in overall agricultural productivity was greater than that in the rest of the economy whereas the reverse had been true since 1896.4 What is even more remarkable is that this improvement should have taken place in the context of continued massive state protection for agriculture, little changed since the days of the Méline tariff introduced in 1892. But whereas protection before the Second World War had tended to rigidify the inefficiency of the agricultural sector, after 1945 protection accompanied the modernization of the agricultural sector. How was such change achieved?