The story has always been presented to me like this...
WWI ends, France decides never to allow that to repeat itself. The Army stubbornly decides to invest in static fortifications, essentially fighting the previous war, while DeGaulle's pleas to invest in aircraft/tanks fall on deaf ears. Then, in 1940, the Germans largely bypass the Maginot Line, and the rest is history.
What would happen if the French invest their Maginot Line resources elsewhere, such as DeGaulle's heavy tanks and planes? From what I understand, the German victory in France was far from guaranteed as it was. How would Blitzkrieg fare against a better prepared France?