During the Second World War, he escaped through Spain to flee the Service du travail obligatoire and joined the Armée française de la Libération in 1943.
[1] A reporter for the Alger républicain in 1945, he met Albert Camus and Jean-Paul Sartre and the latter entrusted to him the management of the magazine Les Temps modernes from 1951 to 1956.
He became acquainted with Emmanuel Mounier, who in 1948 opened for him the doors of the magazine Esprit, where there was a certain 'philocommunism' and who facilitated his entry into the intellectual seraglio of the post-war period.
[2] Beginning in 1957, at the height of the Algerian war, he put his anti-colonial ideals into practice by creating the Jeanson network to transport funds to the National Liberation Front of Algeria.
Fleeing abroad, Francis Jeanson was tried in absentia, convicted of high treason, and sentenced in October 1960 to ten years' imprisonment.