This is generally believed to be George Paudash, his observer looks aboriginal to me. The other fellow is just clowning around in a Germanfield cap.
https://www.milsurps.com/attachment....4&d=1540800502
Paudash is also second from right, front row in this one:
https://www.milsurps.com/attachment....5&d=1540800502
More info about him here.
Seems he served less than a year in Francedue to various medical conditions. IIRC he was already quite an old man when he enlisted and was most unhappy about being sent home.
Photo flipped to show rifle correctly: