During the May Days purge of the Workers' Party of Marxist Unification (POUM) and other anti-Stalinist organisations, which took place in Barcelona towards the end of the Spanish Civil War, many FIJL members were murdered by those acting under Joseph Stalin's orders. After the Civil War, FIJL acted in two branches: one in exile in Paris, and one secret and illegal domestic organisation under Franco's regime. Some FIJL members were associated with the militant First of May Group. FIJL was banned in France in 1963.