Saithis, I wouldn't call it the historic approach. I just loaded up the Blitzkrieg (September 1939) start date for comparison, and that France has 12 more air wings, no dedicated artillery brigades, higher concentrations of infantry along a narrower front, no extended fortifications in the north or improved fortifications in the south, and far less advanced tank technology.
eqqman, if the Germans don't attack me until May (which was the case historically), I still have a chance to push up those critical plains fort ratings in Dunkerque, Hazebrouck, Lille, and Longuyon, which are the only plains provinces on the northern border. Likewise, by May I should have several divisions of heavy armor. A more calculating defensive solution might have been AT brigades in plains provinces, but le CCGG is still thinking in terms of tank divisions that can slowly push a trench warfare front forward.