In 1933 Billotte returned to France, where he served as a Member of the Supreme War Council, President of the Consultative Committee for Colonial Defence and Military Governor of Paris.

When World War II broke out in September 1939, Billotte was 64 and close to retirement, but he was appointed Commander in Chief of the 1st Army Group based in northern France adjacent to the Belgian border.

"[5] Ironside effectively took over the co-ordinating role from Billotte and organised an unsuccessful attack southwards towards Arras in the hope of checking the German advance.

Finally realising the threat posed by the rapid German advance from the Ardennes towards the sea, the French commander-in-chief, General Maxime Weygand, ordered Billotte to withdraw his forces southwards.

At a meeting in Ypres on 21 May, Weygand found Billotte depressed and pessimistic, "heavily marked by the fatigues and anxieties of the past two weeks.

"[6] After leaving this conference, Billotte was severely injured when his staff car was involved in an accident, and died after two days in a coma.