The Char Lourd
In the twenties France used a typology of tanks, classified according to weight. The heaviest class was formed by the Char Lourd, or "heavy tank". In the programmes of 1921 and 1930, no new tank was foreseen for this class, the Char 2C fulfilling the role of Char Lourd. The programme of 1926 led in 1928 to a Char d'Arrêt project of fifty tons; when conceptual studies by FCM had reached 100 tons, a new plan was started in February 1929 for a somewhat lighter 65 ton vehicle, but this was terminated on 17 May 1929 for budgetary reasons.
On 4 May 1936 however, the Conseil Consulatif de l'Armement under General Julien Claude Marie Sosthène Dufieux decided to develop a new heavy tank, with the following specifications given on 12 November 1936: a maximum weight of 45 metric tons, immunity to 75 mm AP fire over a distance of 200 metres, a speed of 30 km/h, a range of 200 kilometres, and an armament consisting of a long 75 mm gun in the hull and a 47 mm gun in a turret. It would thus have resembled an oversized Char B1, of which tank several other development projects were ongoing.
In 1937 three manufacturers, AMX, ARL and FCM, presented prototype proposals; ARL even presented three of them simultaneously. 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. The first designs featured a 37 mm gun. When a better armament was demanded, it was understood through a study by the Section de l'Armement et des Études Techniques (SAET) on 5 April 1937 that the tank would still weigh about twenty tons, while another tank, the Char G1, was already in development in this weight class. 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. Of all projects, the new specifications were most similar to the original FCM proposal of sixty tons and so the French Supreme Command decided on 6 April 1938 to grant FCM a development contract for what was now called the Char F1. 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.
Read more about this topic: FCM F1