In several places they did try to attack the Maginot Line, at Villy la Ferte and Fermont. In these two cases they failed. Villy was only captured as the garrison had been asphixiated when the smoke extracters from their gun turrets packed up... the Germans got in by blowing the doors off and finding the bodies inside. Fermont was never taken; it surrendered well after the fall of France itself. For details of Fermont see:
Fort Fermont
For Villy:
Fort de Villy-la-Ferté (Ardennes ) : ligne Maginot
I have visited both these locations, and they are pretty impressive.