French AT doctrine in 1940 was pretty solid and they would have blunted the Blitzkrieg advance but for positional mistakes at the outset which meant they never got a real chance to try.
tuccyI seem to recall reading somewhere that Germans lost more tanks between Dunkirk and fall of France, than between 1939 and Dunkirk. French Army also seemed to shift to tactics similar to later Eastern Front (basically infantry-and-AT-guns strongpoints instead of regular "line"), but too late.