French overall economic development was lying behind England’s, with its earlier and faster industrialisation. In particular, French agricultural model was considered to be less advanced than the British one. Actually, this impression of economists of the time is confirmed by the comparative calculations (O’Brien and Prados 1992: 518). Its gross domestic product (GDP) was rising more slowly and its rural population remained greater. Many economists considered the weight of the agricultural sector to have impeded the evolution of economical structures. The ratio of agricultural and non agricultural (industry and tertiary) growth rate was 0.67 for the period 180060, 0.1 for 1865-90, 0.5 for 1890-1938 (time of the First World War not included) and 0.67 for 1950-90 (Toutain 1993: 18). What are the reasons of such a difference in growth?