For those interested in the last French battleship designs I recommend French Battleships 19922-1956 by John Jordan and Robert Dumas . This book gives a complete history of the design development of French capital ships from 1922 to the completion of the Jean Bart post war. It also describes the problems that related to the building of large warships in France such as shipyard capabilities, the economy etc. I fully recommend this book to anyone interested in warship design.
On numerous internet sites the most popular option for the last battleship designs being worked on before the French surrender in 1940 is nearly always a 45,000 ton ship with 12 x 15” guns in quad turrets followed at a distance by a similar design of 42,500 tons with 9 x 16” guns in triple turrets. It appears that the leading contender was actually a 40,000 ton design with 9 x 15” guns in triple turrets. The French seem to have decided that the 15” gun was good* but the quad turrets were not such a good idea. (* there was also reluctance to add another weapon to its armoury with the additional support and stores this would have caused).