Hoi Pierre,
Thanks for the ID on the gun mount, I have seen a photo like this IDed as the Paris gun, but I would bet that every Doughboy who saw it thought it was. This photo had not caption, nor does the one above. If yo look close at his collar (he is wearing a US tunic) you can barely make out the medical insignia. I have not been able to put a name to him yet, but he was with the Evacuation Ambulance company # 8. I have a list of all the names of the members of co. 8, and many photos with IDs, so it is possible that he will be named.
Best
Gus