Due to the Washington Naval Conference of 1921 the French Navy was limited to 175,000 tons of battleships. This would allow for five 35,000 ton battleships and discussions started in 1924 to determine what the configuration of the battleships would be.
The French Navy felt that Italy would be their opponent and because of the apparent better speed in Italian battleships it was felt concentrating the main guns forward would work as it was felt that a battle would be mostly a chase.
The London Naval Treaty allowed for France to build 70,000 tons of battleships by the end of 1936.
Authorization for building the Dunkerque was given in 1931. After the announcement by the Italians of building two 35,000 tons battleships it was decided that the second Dunkerque class would have heavier armament.
As there were no dry docks large enough the Dunkerque was built without the sterns in dry dock and they were added after being floated out of the dry dock.
There was one compressed-air catapult to launch the Loire 130.
The hanger had two levels with an elevator between them. One aircraft could be stored on each level.
The main armament was concentrated forward with the secondary armament aft.
The 13" L/50 M1931 guns could fire a 1,200 lb / 1,235 lb AP shell out to 45,600 yards at 35°. Could be fired at 3 rounds/minute. The turret weighed 1,473 tons and was very cramped.
The 5.1" / 13 cm L/45 M1935 guns could fir a 70.8 lb shell out to 22,820 yards at 45°. Could be fired at 10 rounds/minute. The maximum elevation was 75°.
There were three boiler rooms with two oil fired boilers in each.