Late 1937 the project had been renamed Char G1 and all prototypes then authorised had received an official designation: Lorraine: G1L; Renault: G1R; Baudet Donon Rousel: G1B, Fouga: G1Fand SEAM: G1P. The SOMUA and FCM projects were discontinued for being too vague or lacking innovation; also the production capacity of these two companies had already been directed to the manufacture of other types.
On 1 February 1938 the Direction de l'Infanterie issued new specifications, the third major change in the project concept: a maximum weight increased to 35 tonnes, necessitated by the fitting of a Long 32 75 mm gun in a turret
These new demands caused most companies to slow the design process: they were unwilling to invest much money in an ever more complex system, with uncertain prospects. Therefore the French government ordered on 8 June 1938 that ARL military engineer Lavirotte be detached to guide their efforts, in order to speed the proceedings; if the companies could not obtain armour plate, they should be allowed to use boiler plate to construct prototypes. At that moment Renault was unable to give any indication about a possible production date; the Fouga and BDR projects seemed to become prohibitively heavy; SEAM thought to be able to commence manufacture in the middle of 1940 and Lorraine in 1941.
On 12 July 1938 a much more detailed list of specifications was given. In general they called for a tank that is powerfully armed, immune to standard anti-tank guns and possessing an excellent tactical and strategic mobility. In detail they demanded a long high velocity semi-automatic 75 mm main armament; a 7.5mm machine-gun in the turret that can also serve as an AA-weapon; a machine-gun in the front of the hull or the turret; a minimal ammunition load of a hundred rounds for the gun and thirty magazines for the machine-gun; an empty weight of thirty and a combat weight of thirty-two tonnes. The engine should be able to be both electrically and manually started; the tracks should be fully accessible. A maximum speed is demanded of 40 km/h (average 30 km/h) on the road and 20 km/h off-road; two fuel tanks should allow a range of two hundred kilometres or eight hours off-road. The climbing capacity is determined at ninety centimetres and 85% on a solid or 65% on a wet slope; the trench-crossing capacity at 250 centimetres and the wading capacity at 120 centimetres. For the first time also dimensional limits are given: the width should not exceed 294 centimetres to facilitate rail transport, the absolute height of the fighting compartment should not exceed 120 cm, but yet be sufficient to hold a side-door.
As regards the gas-tight armour, the demanded thickness remains at sixty millimetres but it is forbidden to use an appliqué armour. The armour could be cast — with the sections connected by bolts or electrically welded. Automatic fire-extinguishers should be present.
The crew should have advanced vision and fire-control equipment. The cupola, armed with the secondary 7.5 mm machine gun, should have a large episcope to which the main turret is slaved, allowing the commander to lay the 75 mm gun on the target himself — which is very desirable as he doubles as gunner. The cupola should also be fitted with an optical telemetric rangefinder. The gun is a Long 32 75 mm gun, providing, despite its limited elongation compared to foreign weapons, a good muzzle velocity through the use of Brandt tungsten armour-piercing subcalibre ammunition.
None of the projects in the summer of 1938 could meet these specifications without a fundamental redesign.