Monatte was born on 15 January 1881. Alphonse Merrheim arrived in Paris in 1904, and soon afterward, he met Monatte at the office of Pages Libres. The two men would work together to launch La Vie Ouvrière (The Worker's Life).[1]
In 1914 Monatte and Alfred Rosmer led the internationalist core of La Vie ouvrière (The Worker's Life).[2]
Monatte often referred himself to Fernand Pelloutier and did not disguise his anarchist sympathies although he drifted away from that current of socialism after the International Anarchist Congress of Amsterdam in 1907. There, Monatte argued in particular with Errico Malatesta concerning the methods of organisation. Invoking the 1906 Charter of Amiens, which established the principle of "political neutrality" of trade unions, Monatte considered syndicalism itself to be revolutionary, but Malatesta advocated the creation of some sort of anarchist organisation to superate internal conflicts among the workers' movement itself.[3]
At the CGT's first postwar congress, held in Lyon from 15 to 21 September 1919, Monatte was among the leaders of the minority, with Joseph Tommasi, Raymond Péricat and Gaston Monmousseau and denounced the CGT membership in the Amsterdam International of Labor Unions. They claimed that the CGT majority had broken with the principles of syndicalism and lost faith in revolution by dealing with the government. The minority wanted the CGT to join the Communist International.[6]