This paper is related to the application of the land policies implemented in France in 2nd half of the 20th century, and their consequences on the economy of the agricultural sector and the operation of the farms. Starting from a framework of historical and institutional analysis, the object of this research is to analyse the economic and institutional determinants of these land policies. In France of small landowners, the existence of the right of ownership is considered as an obstacle for a fast evolution of the structures of farms which are sufficient size to implement technological progress allowing the profits of productivity. The aim of the land policy followed in France since the end of the Second World War was to encourage the development of such farms. The main measures were the statute of the tenant farming, the control of the structures and the control of the land market by the SAFER. This policy is implemented at a departmental level by the representatives of the Farmers Unions and generally supports the access to the land for young farmers or the middle-sized farmers.