"France Soir" was founded as the underground paper "Défense de la France" ("Defense of France") by young resistance leaders, Robert Salmon and Philippe Viannay, in 1941. The first editions were printed on a Rotaprint 3 offset printing machine hidden in the cellars of the Sorbonne. Distributed to Grenoble, Clermont-Ferrand, Lyon and to Britain by the resistance networks Combat and Témoignage chrétien, "Défense de la France" became the largest circulation newspaper in the underground press, with 450,000 copies per day by January 1944. In March 1944, after multiple relocations, it was housed on three levels of an industrial building on rue Jean-Dolent, behind the La Santé Prison, in Paris's XIVth arrondissement.