Jacques Duclos was born in France in 1896. He became a baker and joined the Communist Party. In 1926 he was elected as a member of the party's central committee.
The Communist Party had been banned by the French government after the signing of the Nazi-Soviet Pact in July, 1939. Maurice Thorez, leader of the party, went to live in Moscow and Duclos went into hiding and became the main spokesman of the underground party in France.
Duclos helped edit the underground newspaper, L'Humanité, and it called for a "National front for the independence of France." In May 1942, Duclos and Pierre Villon established the communist-based resistance group, Front National. He also helped to direct the Frances-Tireurs Partisans, the military wing on the Communist Party.
After the war Duclos was elected to the National Assembly and in 1959 joined the Senate. Jacques Duclos died in 1975.