At the age of 22, Jean moved to Paris, where he renewed his childhood friendship with François Mauriac (the latter was to recall the former frequently, most notably in La Rencontre avec Barrès, 1945).
Jean held a government post at the prefectory of the Seine where he was responsible for assisting the elderly.
His Lettres de guerre develop movingly from initial enthusiasm for the defense of Civilization and a conviction that the enemy was the entire German people, through a growing irritation with chauvinistic brainwashing and the flagrancy of what would now be called the 'disinformation' peddled through the French press (so much more heavily censored than the British, he said), to an eventual admiration, at the front, for the heroism and humanity often shown by the enemy.
La Ville de Mirmont was still alive when his comrades dug him out, but the explosion had broken his spine and he died soon afterwards.
His main works are: Also: His work developed from a romantic concern with the ocean and sea-voyages - influenced by Baudelaire and Jules Laforgue, and described by himself as "steeped in vague rhetoric/in romanticism"[7] - to sharper, hard-edged views of contemporary Parisian life, as seen in his later contes and in his novel: to a concern above all (in his own words) with the "humdrum routine of human existence".