Marcel Bleibtreu (26 August 1918 – 25 December 2001) was a French trotskyist activist and theorist. Bleibtreu was born during his family's refuge in Marseille from wartime bombing, Marcel Bleibtreu became a radical thinker as a child. After studies at the lycée Condorcet, he studied medicine in Paris, and graduated in 1947. He joined the Groupe Bolchevik Léniniste, the Trotskyist organisation, in September 1936. By 1944 the GBL had merged with two other Trotskyist currents to form the Internationalist Communist Party, (PCI), the French section of the Fourth International. Bleibtreu led workplace cells of the PCI around Puteaux-Suresnes-Nanterre under the pen-name Pierre Favre. In November 1944, he became an editor of the party's journal, La Vérité. He was named general secretary of the PCI