[1] When the World War I broke out, he volunteered in November 1914 with the 22nd Colonial Infantry Regiment (22nd RIC).
He was cited in the army order, decorated with the military medal and the croix de guerre with palm.
[4] He received his Agrégation in philosophy in 1922 and was appointed the following year to the high school in Constantine (Algeria).
A member of the Croix-de-Feu and the French Social Party of Colonel de la Rocque, he narrowly failed in the 1932 legislative elections.
On 10 July 1940, Devaud voted in favour of granting the cabinet presided by Marchal Philippe Pétain authority to draw up a new constitution, thereby effectively ending the French Third Republic and establishing Vichy France.