[3] As a socialist activist, he participated in the creation of the union of agricultural workers and shared the peaceful ideas of Jean Jaurès.

[4] For four years he fought in the most dangerous sectors of the front: Notre-Dame-de-Lorette, Verdun, the Somme, and the Chemin des Dames.

He transcribed his diaries and letters into 19 notebooks, pasting in picture postcards, illustrations, and maps clipped from newspapers and magazines.

The squad is like a little family, a center of affection where deep feelings prevail, of solidarity, mutual devotion, intimacy, and from which the officer and even the sergeant are excluded.

[6]On a memorial to the fallen of World War I in Pontcharra-sur-Bréda in the Département Isère, a quote of Barthas' diary is engraved, reading: Often I think of the great number of companions who fell at my side.