Construction of the battleship was made possible after the French government signed the Washington Naval Treaty. It allowed for construction of three battleships displacing 35 000 tons each and building of the first one could be commenced in 1927.
Two additional ships were planned in two-year intervals – in 1929 and 1931 respectively. French delegation was able to force through that exemption under the terms of the treaty as a compensation for the fact that the French navy was unable to build battleships during the World War I. In 1924, the first draft of the future shipbuilding program, which concentrated on light units, was being prepared. Construction of new battleship was first discussed in 1926, when the units of the Provence class had already been ten years in the service. The Staff of the French Navy (EMG – Etat Major General) requested the STCN (Section Technique de Constructions Navales – similar to the Naval Ship Engineering Center in the U.S. Navy) to prepare a design of “battle cruisers” (croiseurs de combat) that would meet the following three requirements. First, they were to be capable of destroying each treaty cruiser that would be commissioned by major naval powers. Second, they would be able to attack merchantmen in convoys protected by battleships with speeds of 20 to 25 knots. Third, they would become part of the scouting force. These requirements related mainly to the colonial nature of the country, whose priority at that time was protection of its shipping lanes, were not difficult to meet. In 1926 several preliminary designs of 17 500 tons cruisers armed with 330 mm guns were prepared. In 1928, when the Germany announced the construction of 10 000 tons Deutschland class warships, the new design work on units which would have both heavier armour and armament was commenced. In the meantime, two disarmament conferences were held, first in Geneva in 1927 and the second in London in 1930. Governments of Great Britain and the United States strived to retain the position guaranteed by the Washington Naval Treaty and prevent construction of larger battleships. Majority of countries had already been aware that disarmament treaties would soon be a thing of the past. They were also surprised by the fact that Germany joined the new armament race.
Table 1. Design requirements of the battleship Richelieu
Displacement (standard) 35 000 tons
Main battery Eight or nine 15 or 16-inch guns mounted in triple or quadruple turrets
Secondary battery The same as the Dunkerque class
Speed 29.5 – 32 knots
Main side belt 360 mm, sloped at 11.3°
Upper armour deck 160 mm
Lower armour deck 40 mm