French labour-union federation that is most influential among white-collar civil servants and clerical workers. It was formed in 1948 after a split within the General Confederation of Labour (Confédération Générale du Travail, or CGT). In 1947 the socialist minority withdrew from the CGT after communists had gained control of the federation's leadership apparatus. The socialists' departure was triggered by the CGT's communist-inspired policy of fomenting violent strikes that seemed intended to destabilize the new government of the Fourth Republic. The departing socialists formed a new confederation, the CGT–FO, under the leadership of Léon Jouhaux, who had been secretary-general of the CGT from 1909 to 1946.

In the decades since its founding, the CGT–FO has remained smaller than the CGT and has mainly represented salaried workers and those in the public-service sector. The CGT–FO is socialist in outlook but is not officially connected with the French Socialist Party. It is a member of the International Confederation of Free Trade Unions, which Jouhaux helped to found.