In the years before the outbreak of World War I in 1914, the French Navy considered several proposals for battlecruisers. The Navy issued specifications for a battlecruiser design to complete part of the 28 capital ships to be built by 1920. Three designs, one by P. Gille and two by Lieutenant Durand-Viel, were completed in 1913. All three designs were similar to contemporary battleship designs, specifically the, which introduced a quadruple gun turret for the main battery, which was adopted for all three proposals. The first two called for the same gun used on all French super-dreadnoughts, though the third proposed a much more powerful gun. Though the design studies were complete, the French Navy did not authorize or begin construction of any battlecruisers before the start of the war.
In the Naval Law of 30 March 1912, the French Navy called for a total force of 20 capital ships to be built by 1920. The Technical Branch subsequently issued a set of somewhat vague requirements for battlecruiser designs. The requirements stipulated a displacement of 28000MT, a speed of 27kn, an armament of eight 340mm guns, and a crew of not more than 1,200 officers and enlisted men. These figures were very similar to the British s then under construction. Numerous proposals were submitted to the Technical Branch, but only two were evaluated further. The first was prepared by P. Gille, a naval engineer overseeing the construction of the, and the second by then-Lieutenant Durand-Viel, a student at the Naval College. As the proposals were only design studies, none were authorized and no ships were built; the outbreak of World War I ensured that even more advanced projects, like the Normandie and s were canceled as resources were redirected toward more pressing needs.
In 1911, Gille went to Britain to observe the construction of the new s and the Lion-class battlecruisers. The latter ships prompted Gille to decide the French Navy ought to build battlecruisers as well, since Britain and Germany had already begun acquiring them, and they would prove useful as a fast division of the French fleet. Gille decided that his proposed ship would need a top speed of 28kn29kn to retain an advantage over foreign battleships, the latest of which had estimated speeds of 22kn23kn. They would also need enough armor and a main battery powerful enough to fight in the line of battle. The limitations that weight imposed on the design, however, restricted the amount of armor possible, and so the traditional French practice of armoring the entire side of the ship would be impossible.
Gille's battlecruiser design called for a displacement of 28247MT on a hull that was 205m (673feet) long between perpendiculars, with a beam of 27m (89feet) at the waterline and an average draft of 9.03m (29.63feet). The freeboard forward was 7.15m (23.46feet), and aft was 4.65m (15.26feet). The hull lines of the ships proved to be highly efficient in tank tests during the design process. Due to the extreme weight of the main battery turrets at the bow and stern, the hull had to be strengthened to handle the strain. Very strong longitudinal bracing was incorporated, and the inner and outer skins of the hull was thickened to reinforce the bracings. The ships' expected metacentric height was 1.03m (03.38feet), comparable to the British Lion class. Each ship would be crewed by 41 officers and 1,258 enlisted men.
The ships would have been equipped with four sets of steam turbines rated at 80000shp powered by fifty-two coal-fired Belleville boilers. Each propeller shaft was connected to a high-pressure turbine, a medium-pressure geared turbine, and a low-pressure turbine for forward steaming, and a direct drive turbine for steaming in reverse. The ships' top speed was to have been 28 knots. The ships would have been supplied with 2833MT of coal and 630MT of fuel oil for supplementary oil firing. At maximum speed, the ships could have cruised for 1660nmi; at 20.3kn, the range increased to 4240nmi, an at a more economical 15kn, the range grew to 6300nmi.
The ships' main armament was composed of twelve 340mm/45 Modèle 1912 guns in three quadruple turrets, the same as in the contemporary French battleships of the Normandie class. One turret was placed forward, and the other two were placed in a superfiring pair, all on the centerline. The guns had a range of 16000m (52,000feet) and had a rate of fire of two rounds per minute. The shells were 540kg (1,190lb) armor-piercing rounds and were fired with a muzzle velocity of 800m/s. A secondary battery of twenty-four 138.6 mm /55 Modèle 1910 guns mounted in casemates was planned for defense against torpedo boats. These guns fired a 36.5kg (80.5lb) shell at a muzzle velocity of 830m/s. The armament was rounded out by six torpedo tubes of undetermined diameter, all submerged in the ships' hulls.
The armor protecting both the main armored belt amidships and the main battery turrets was 270mm thick. The lower armored deck was 20mm thick, with 50mm of armor plating on the sloped sides. The casemate guns were protected with 180mm of steel armor. The ships were also equipped with a 20 mm thick torpedo bulkhead.
Durand-Viel's first battlecruiser design, "A", was built on a displacement of 27500MT. The hull was 210m (690feet) long at the waterline, with a beam of 27m (89feet) at the waterline and an average draft of 8.7m (28.5feet). The ships would have been equipped with four sets of direct drive turbines rated at powered by twenty-four double-ended Belleville boilers that burned both coal and oil. The ships' top speed was to have been . The ships would have been supplied with 1810MT of coal and 1050MT of fuel oil . The ships could have cruised for at 16kn, with enough fuel for an additional six hours for combat speeds.
The ships' main armament was composed of eight 340mm/45 Modèle 1912 guns in two quadruple turrets, the same as in the contemporary French battleships of the Normandie class. Both turrets were placed on the centerline, on either end of the ship. A secondary battery of twenty-four 138.6 mm Modèle 1910 guns mounted in casemates was planned for defense against torpedo boats. Four 47mm saluting guns were also to be equipped. The armament was rounded out by four 450mm torpedo tubes, all submerged in the ships' hulls. The main armored belt amidships was 280mm thick, slightly thinner than the belt on the Normandie-class battleships. The rest of the ship's armor was very similar to that of the Normandie class.
The ships' main armament was composed of eight 370mm guns in two quadruple turrets. Both turrets were placed on the centerline, on either end of the ship. The gun fired a 880kg (1,940lb) shell that was capable of penetrating 300mm of armor plate at a range of 12700m (41,700feet). A secondary battery for defense against torpedo boats consisted of twenty-eight 138.6 mm guns, of a new semi-automatic design, mounted in casemates. Four 47 mm saluting guns were also to be installed. The should would also to have carried four 450 mm torpedo tubes, all submerged in the ships' hulls. The ships' armor system was identical to the "A" design.