 He was a passionate anti-Stalinist, rejecting support from the Red Aid, a front organisation of the French Communist Party, when he was prosecuted by the French authorities for an anti-militarist article.In 1936, he served in the Sébastien Faure Century, the French-speaking section of the Durruti Column, an anarchist anti-Francoist militia in Spain.In October 1936, he became the general delegate for foreign groups, replacing Bethomieu who died in Perdiguera.