No, France is not fitting a 140mm gun to its Leclerc tanks. Trials last year by Nexter with 140mm were to gather more data on how a large gun affects a 3rd gen tank chassis (overpressures etc), informing MGCS concept studies.

More at @MILTECH1:https://t.co/el2AhMa5ud pic.twitter.com/axHT1pwVJl

— grant turnbull (@turnbulljourno) January 25, 2019