The Maginot line had a trinity of firepower, protection and obstacles.
The Border Post line would give alarm and prevent enemy surprice attacks.
3 miles behind the border was the Support Point line, with Flood Zones were basins and rivers could be flooded on demand, behind that was mine-fields with anti-tank obstacles, followed by anti-personel barbed wire.
6 miles behind the border was the Principal line of concrete bunkers with infantry, snipers, twin-machine guns, anti-tank guns and heavy artillery. Behind that was Observation Posts that directed the fire, supply depots and armoured reserves to counter attack…
It would be suicide to attack a fortified line like this. The defenders was protected by concrete bunkers and immune to fire, while the attackers was sitting ducks in a mine-field with obstacles and barbed wire. The only time an attack like this succeeded was on Eben Emael, and that was because Belgium was not at war, and did not expect any attacks.
In light of this, it seems difficult to model this in an A&A game. It would be a very expensive piece, like a Blockhouse that cost 15 IPC, cant move, take 4 hits before its killed, roll a dice on 4 or less for hit when defending, and half the attackers value. This Blockhouse piece can only be placed on a land/land border or sea/land border, and faced only one way. If you attack from another direction, the unit is by-passed. To model the mine-field, the attackers are halfed, so two infantry roll like one die etc.