The Richelieu class were fast battleships built for the French Navy between the 1930s and 1950s. Initially two ships were ordered in 1935 in response to Italian orders for the Littorio-class battleships the previous year. The Richelieus were based on the preceding Dunkerque class, but scaled up to accommodate more powerful 380 mm (15 in) guns and armor to protect them from guns of the same caliber. To keep the ships within the displacement limits imposed by the Washington Naval Treaty, they featured the same concentrated arrangement as the Dunkerques for the main battery: two quadruple gun turrets placed forward. They also incorporated new, more compact boilers that allowed for a shorter hull (which required less heavy armor) for the desired top speed. After Germany ordered two Bismarck-class battleships, France responded with another pair of Richelieus, but built to modified designs. The first, Clemenceau, received modified secondary and anti-aircraft batteries, while Gascogne had her superfiring main battery turret shifted aft, along with other changes.





By 1937, tensions in Europe had increased significantly as Germany and Italy took increasingly aggressive positions, raising the likelihood of war in the near future. German naval construction was at that time directed against France; the two Scharnhorst-class battleshipshad been laid down to counter the Dunkerques and the two Bismarck-class battleships had been ordered to match the two Richelieus. Since the two French battleships had been ordered in response to the expanding Italian fleet, the French naval command determined that another pair of battleships would be needed to balance the Bismarcks. Two ships were authorized on 2 May 1938 under the names Clemenceau and Gascogne. But delays in the construction program, owing to a shortage of dockyards large enough to handle additional hulls of this size, allowed time for additional design studies at the request of the naval command.^[20]

The command wanted to compare their new ships with the latest foreign contemporaries; they noted that all other battleships carried their main armament forward and aft, and several of them used dedicated high and low-angle guns for their secondary batteries. The 130 mm dual-purpose guns used on the Dunkerques were proving to be troublesome in service, and the command wanted to determine whether the arrangement would be suitable for future construction. Vice-Amiral François Darlan, who had by now replaced Durand-Viel as Chief of Staff, issued a request for studies on 2 December 1937 with the requirements that the proposals be based on the Richelieu design, armed with eight or nine 380 mm guns in quadruple or triple turrets, equipped with a secondary battery of 152 mm or 130 mm dual-purpose guns or a mixed battery of 152 mm and 100 mm guns, and with armor on the same scale as Richelieu. A series of proposals were submitted, ranging from effective repeats of the Richelieu design with minor improvements (the Project A series) to plans that shifted the superfiring main battery turret aft of the superstructure (the Project B series), to the nine-gun variants that kept two triple turrets forward and a third aft (the Project C series). All three basic formats included several variations that incorporated changes to the composition and arrangement of the secondary and anti-aircraft batteries.^[21]

The Project C variants all displaced close to 40,000 long tons (41,000 t) and thus were not seriously considered, as they exceeded the displacement limits by a wide margin. The designers submitted the A and B variants to Darlan on 19 March 1938 and he chose one version of each for Clemenceau and Gascogne, respectively. As a result, the former would retain the basic Richelieu layout, while the latter would adopt an arrangement with one main battery turret shifted aft. Both variants necessitated significant changes to the arrangement of other equipment, including the light anti-aircraft batteries and aviation facilities, but Gascogne required much more radical work. The rest of the naval command preferred the B version adopted for Gascogne and questioned why Darlan had approved the A variant for Clemenceau; he stated that he hoped to be able to lay down the third Richelieu-class ship in late 1938 and that the necessary redesign work for the hull interior that the B variant required would delay construction by twelve months at a minimum. The command concurred and authorization for the next ship was issued on 24 August.^[22]