Neosocialism was a political trend of socialism, represented in France during the 1930s and in Belgium, which included several revisionist tendencies in the French Section of the Workers' International (SFIO). In the wake of the Great Depression, a group of right-wing members, led by Henri de Man in Belgium, founder of planisme, and in France Marcel Déat, Pierre Renaudel, René Belin, the "neo-Turks" of the Radical-Socialist Party (Pierre Mendès-France, etc.