So the gas mask in the game is this one: https://collection.sciencemuseumgroup.org.uk/objects/co148735/gas-mask-germany-1...
The british are dating the mask to 1915.
What you have seen is correct, the french soldier (the player) is also using the german gas mask. Thats because of crunch time. So we just used the same asset twice x)
But I could be wrong. Thanks for showing me that! I understand the time crunch, and if i'm being honest, I kinda like the german masks better