Interesting french twin turret heavy tank design I ve found in wakipedia. This super-heavy armored vehicle had some resemblance to the russian T-100 and SMK.
The FCM F1 was a French super-heavy tank developed during the Interbellum by the Forges et Chantiers de la Méditerranée company. 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 FCM F1 was large and elongated, and had two turrets: one in front and one in the back, with a single high-velocity gun in each turret. The rear turret was higher so it could shoot over the first one. The vehicle was intended to be heavily armoured. Its size and protection level made it early 1940 with about 140 tons the heaviest tank actually ordered. Despite two engines its speed would have been slow. The primary purpose of the tank was to breach German fortification lines, not to fight enemy tanks. 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. For each project again several companies submitted one or more competing proposals.
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 a 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 asked for a superheavy tank with a 75 mm gun in a turret; no weight limits were imposed. The new specifications were closest 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 a Char F1. It was realised however that this project could be no more than an intermediate step in heavy tank design and already a special commission had been formed in February, headed by the inspector-general of tanks, Julien François René Martin, to further study the problem of overcoming the new defences of the Westwall being at the time constructed on the western German border.