He undertook his military service in Paris in 1930 -- 31 , and on return became an active SFIO militant .
He joined the French Section of the Workers ' International ( SFIO ) in 1926 .
He undertook his military service in Paris in 1930 -- 31 , and on return became an active French Section of the Workers ' International militant .
He joined the French Section of the Workers ' International ( SFIO ) in 1926 .