He studied at Lycée Janson-de-Sailly in Paris before enlisting in the French Army during World War I before his eighteenth birthday.

After the war, he pursued law studies and worked for Hubert Lyautey, Resident-General of French Morocco.

[1] He married Andrée Viénot, daughter of Luxembourg businessman and patron of the Franco-German committee Émile Mayrisch, in 1929.

He negotiated independence treaties for Lebanon and Syria in 1936, though these were not ratified due to opposition in the French Senate.

In 1938, he opposed the Munich Agreement and co-founded the socialist group "Agir" alongside Pierre Brossolette and Daniel Mayer, advocating resistance against Nazi Germany.