Bertrand was born in 1888 in Nyons, Drôme, and after attending his local school, he departed for Paris, where he worked as a journalist on a number of papers, including "Paris-Midi" and "L'Homme libre". During this period, he also began a literary magazine named "Les Chiméres", which he used as a vehicle to publicise his socialist ideas and surrealist poetry, as well as give a voice to people of a like mind. Bertrand was a confirmed pacifist and just short of his 26th birthday when the First World War began, but nonetheless joined the French Army immediately, being given a position in the cavalry. For the next three months he was continuously engaged in the Battle of the Frontiers against the German Army and made a name for himself in his unit with some daring exploits.