This paper is discussed on the process of the nationalization of the Bank of France and the four big deposit banks and also on the method of credit control. It was in 1936 under the government of "Front populaire" that the Bank of France started its first step to the nationalization. Since then, some attempt of reorganization was made during the World War II, but towards the end of 1945 after the "liberation", the radical reconstruction was carried out to the effect that the Bank of France was completely nationalization with other four big banks. The nationalization of the Bank of France is not entirely caused by the economic reason, but seems to be due to the social and political reason. This is clearly understood from the process of it. In this point we can say the nature of the nationalization is a little different from that of the Bank of England. The fundamental idea was to get rid of dominion upon the Bank of France by a few people and also upon the French politics and economy itself by the minority. In other words we might call it the socialization based on the socialism. Therefore the system of the control of the financial policy came to be adjusted and strengthened with the realization of the nationalization of the Bank of France. The aim of this treatise is to make clear the manifold situations which stimulated the nationalization of the Bank of France, especially its social and political back-ground, investigating the process of it.