After completion, Duguay-Trouin was assigned to the 2nd Squadron and based at Brest. In 1929, she became flagship of the 3rd Light Division in the Mediterranean and, in 1931, she undertook an extended cruise to Indo-China, then a French colony. Duguay-Trouin returned to the 2nd Squadron at Brest in 1932, this time as flagship, remaining there until 1935. In 1936, she became a gunnery training ship until June 1939, when she joined the 6th Cruiser Division.