On May 12th, 1962, the West African Monetary Union was established by treaty between six French-speaking African states, Senegal, Ivory Coast, Upper Volta, Niger and Dahomey. This Union is linked with France by a system of “operations accounts” concluded between the French Treasury and individual issuing banks. The system ensures the free inter-state convertibility of their currencies and with the French franc, the C.F.A.F. (Communauté Financière Africaine Franc) being guaranteed by the French Republic. Under this system commercial and financial transactions are free within this monetary area, and within the Franc Zone. A common central bank, the Central Bank of West African States, was set up.