Neosocialism was a political faction that existed in France and Belgium during the 1930s and which included several revisionist tendencies in the French Section of the Workers' International (SFIO).

Marcel Déat was a French politician. Initially a socialist and a member of the French Section of the Workers' International (SFIO), he led a breakaway group of right-wing Neosocialists out of the SFIO in 1933. During the occupation of France by Nazi Germany, he founded the collaborationist National Popular Rally (RNP). In 1944, he became Minister of Labour and National Solidarity in Pierre Laval's government in Vichy, before escaping to the Sigmaringen enclave along with Vichy officials after the Allied landings in Normandy. Condemned in absentia for collaborationism, he died while still in hiding in Italy.