Twelve were ordered in 1940 to replace the char 2C, but France was defeated before construction could begin, a wooden mock-up being all that was finished.

The rear turret was superfiring, meaning it was raised higher and fired over the top of the forward one, a common practice in naval vessels.

The development path of the FCM F1 was extremely complex, due to the existence of a number of parallel super-heavy tank projects with overlapping design goals, the specifications of which were regularly changed.

When conceptual studies by FCM had reached 100 tonnes, it was feared such a heavy vehicle would have insurmountable steering problems.

By the end of July an articulated tank was foreseen, with a separate tracked motor and double gun module, each weighing about seventy to eighty tonnes and featuring 100 mm armour.

[2] In June 1929, the STCC (Section Techniques des Chars de Combat) began another heavy tank study, proposing a faster design with a Johnson track, an engine of 500 hp, a speed of 12 km/h, 65 tonne weight, a turreted 120 mm gun and 50 mm front protection.

All of these however, even in this early stage of development had a higher projected weight than 45 tons — and threatened to become even heavier during actual construction.

In reaction, the Conseil Supérieur de la Guerre initially decided on 26 March 1937 to build a very small and cheap but heavily armoured (60 mm) vehicle instead, on the lines of the British Matilda I.

As a result, in February 1938 the specifications were again radically changed, and now called for a superheavy tank with a 75 mm gun in a turret; no weight limits were imposed.

It was nonetheless realised that this project could be no more than an intermediate step in heavy tank design; already, also in February, a special commission had been formed, headed by the inspector-general of tanks, Julien François René Martin, to further study the problem of overcoming the new defences of the Westwall (often incorrectly called the "Siegfried Line") being constructed at the time on the western German border.

[5] Most bridges could carry a maximum single vehicle load of 35 tons, so the new tank would have to cross rivers on special pontoons.

It retained two options: the char maximum of 89 tons, demountable in two sections, and the char squelette of 110 tons and with a trench-crossing ability of eight metres; this latter design was along the general lines of the World War I American Skeleton Tank, but with the added feature that the main body could move in relation to the skeleton track frame in order to shift its point of gravity.

When the Second World War broke out in September 1939 some hurried measures were taken to have an operational heavy tank ready for the planned offensive against Germany in 1941, even though the French High Command did not have great faith in the super-heavy tank project and intended to circumvent the Westwall by violating the neutrality of the Low Countries, should these refuse to join the Entente in time.

Despite the hurry, the lack of real progress made did not allow for a concentration of all effort into a single design, as it was still unclear whether a working prototype could be provided in time.

That month both FCM and ARL indicated that they expected to begin construction of the prototypes in the summer of 1940 and series production at the end of 1941; for AMX it was too soon to make any precise predictions.

In February 1940 the Société d’Études et d’Application Mécanique (SEAM) proposed a tank designed by the Polish engineer Prince André Poniatowski.

The project tried to recommend itself by pointing out that the hull was over five meters wide while being only twelve metres long and thus had a superior length-width ratio, facilitating steering.

The subcommission advised to go ahead with both the FCM F1 and the ARL tracteur C prototypes and immediately place an order for ten or fifteen of the former.

The Commission decided to abandon the ARL projects and make a preliminary order for twelve FCM F1s, to be delivered from May 1941 onward at three or four tanks a month.

The Commission also asked FCM to bring the armour protection to 120 mm all-round, though this would increase weight to 145 tons and reduce maximum speed to 20 km/h.