Yeah, I don't play Hearts of Iron 4 (if that is what you're talking about), but what I do know was that the Maginot line was the main French-Defense thing in WWII against the Nazis. It was essentially a big line of French forces on its border, hence the name Maginot Line. The Nazis got through, anyway. But, I don't play HOI4, so idk what that means, I could be wrong.
the thing is that I played that game and ruined the whole thing by building level 6 forts all throuth the german-soviet border. In the game the maginot is a line with level 10 forts and is bacicly inpassable