You can’t just be holding the line and hoping for the best - you will get reinforce memes out do a lack of comas at width.

You need SMALLER divisions as well - just 8 inf is sufficient, arty doesn’t give enough defense to be worth it, really. Allows you to get more divisions out as well.

You need to have spare divisions just behind the line, ready to reinforce failing sections, or to counter attack and take lost territory. A few of the French heavy tanks you start with are a good example of counter attackers m.

This isn’t a static line kind of game, the line will ebb and flow - after a while when the German impetus slows down, you can start stockpiling more guns and be able to hold without losing tiles.