France designs against Littorio, not a weaker Bismarck

How would France respond if Germany built a 35,000-ton Bismarck with 13-inch guns?

French plans change little because the fleet still has to counter Italy's more heavily armed Littorio class.

French design choices would still reflect a two-opponent Mediterranean and European problem. Italy's Littorio-class battleships would carry 15-inch guns, making them the stronger benchmark even if Bismarck were reduced to 13-inch weapons. France would therefore build the most powerful ships it could against the Italian threat rather than create a separate weaker standard for Germany. A battleship able to meet Littorio should also be able to handle the altered German ship. Procurement follows the most demanding credible opponent rather than every rival independently.