[3] After being demobilized Catelas joined the French Northern Railway (Compagnie des chemins de fer du Nord) as a brakeman.

[1] Catelas was an active supporter of the Republican side during the Spanish Civil War (1936–39) and made frequent visits to Spain to see how they could be helped.

On 14 July 1938 he joined the French volunteers in the brigade called "La Marseillaise" in preparation for an attack in the Battle of the Ebro that was launched eleven days later.

[2] After the outbreak of World War II (1939–45) Catelas remained a PCF member, and under the law of 20 January 1940 lost his seat in the Chamber of Deputies.

[4] After the armistice of 22 June 1940 the PCF leaders denounced the imperialist war, called for peace and concentrated on opposition to the Vichy government.

[5] Catelas and Maurice Tréand began negotiations with the German ambassador for permission to resume open publication of the communist journal l'Humanité.

[6] A confidential police report on a clandestine meeting of communist militants on 24 July 1940 gave the attendees as Catelas, Eugène Hénaff and others.