Apparently folks like LK don't know that such units exist, so maybe I should include them rather than assume everybody realizes they are there and will be used. I did mention in my proposed order of battle that such units might be grouped with a regular or reserve corps to create an Armee Abteilung covering the Ardennes... maybe that was too subtle.
But otherwise I've not explicitly enumerated them in my various posts.
Unfortunately folks like you have no sense of the actual French order of Battle and how fast they will quickly add to their forces. This was one of the main reasons for their recovery at the Marne
The table:
active army.......................................................994,000
25 reserve divisions...........................................450,000
12 Territorial divisons.........................................184,600
Cavalry...............................................................52,500
Army troops......................................................187,500
Fortress garrisons..............................................821,400
GVC.................................................................210,000
Depots..............................................................680,000
Total...............................................................3,580,000
Source- Edward Spears Liason
Now, combing through this mass we have a rather large force to deal with your tiny 40 divisions and for the French to make good their losses
The Territorials and troops brought up from the Fortresses (the Germans do this OTl so I'm sure the French won't think of it or can't do it in the minds of some in this thread) to mask the German and/or Belgian fortresses that they may need
The GVC were detachments to guard communications in the rear. In OTL they are disbanded even with the German thrust into France. With the Germans chasing after the Russians, they are getting disbanded and used to fill the ranks
The depot troops are specifically for building units back up to strength. They do include men called up for training and will start becoming available by the end of September
The Germans make a huge roll of the dice- they threw everything in to their offensive so it is the Germans who are going to have more trouble making good their losses. Especially given the need to make good the much higher losses they will be facing in the East