Maginot Line v. 1.7
One of the deployment hexes is on an exit hex. (The one in the south. You narrowly missed the one in the north.

)
Well, I hate to be a nitpicker, but that is what you are paying me for. With the "Capture Sarrebourg" objective that states, as does the others, "Use the captured fortress guns against their former owners," what the player is capturing is a
concrete bunker, unlike the others. It doesn't seem right to spawn a fortress in the place of it.
Therefore, I advocate switching these two structures:

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According to this description, I consider the four fortresses to be "Gros Ouvrages" and the concrete bunkers to be "Petits Ouvrages":

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and the primary objectives should be "Gros Ouvrages" in my opinion.
Actually, the real fortresses of the Maginot Line were in places like Verdun, Toul, Épinal, and Belfort as well as Metz according to
this source. However, your placing fortresses at Meta, Longyon (Is that spelled "Longuyon," by the way? If so, please correct the map and the mission), Falquemont, and Sarrebourg gets the point across nicely - this is supposed to be a simulation after all.
As I was researching that information, I ran across a great photo and I feel compelled to offer it to you to add a bit of flavor in this last scenario of the campaign:
Title: The Maginot Line
Image: french_troops_manning_maginot_line
Text: The French are now manning the fortifications of their now useless Maginot Line in a last ditch effort to save their country from defeat. These are brave men. It is unfortunate that their stubbornness must end in extermination. However, this is war and we have tasks to accomplish that will bring an end to it. Proceed with your mission.
Here is the image:

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I think this looks rather good, but you be the judge and if you agree, then use the materials above. I have it set for Turn 1:

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