Étienne Monier was born into a family of winegrowers in Estagel, in Pyrénées-Orientales, a small town with a strong anarchist tradition since the local population resisted Napoléon III taking power in 1851.
[2] Monier left home at 18 and found work as a gardener in Alais and Nîmes,[2] before deciding to move to Paris in 1909, where he became close with André Lorulot.
[3] Monier and others like him disagreed with Léon Jouhaux, who advocated for revolutionaries to join the army and disseminate anarchist propaganda among the soldiers,[2] so in December 1910 he left for Belgium to avoid military service.
[3] On 25 March 1912, the gang, including Étienne Monier, stole a de Dion-Bouton automobile in the Forest of Sénart south of Paris and shot the driver through the heart.
Gausy gave shelter to Bonnot later, though he told the police he had been introduced to him by Monier as a Russian revolutionary hiding out after the Lena massacre.