Film found inside a Kodak Hawkeye pocket folder from the 30's that I bought in a flea market. I had to modify a spool to process it and eyeball the developper time (Microphen stock, 7'30" at 20°C), but I was lucky enough to get results, yay! The film was Kodak Verichrome Pan (116), which started in the 50's, that's the only clue I have as to the age of the photos, though the clothes look like the 60's.
After a bit of online research, I found a reference to the man burried at this location. Maniez Henri (from the name on the tombstone) was born in 1889 and was killed in Aubérive, from what I gather, when german troops took the city in 1915 and later fortified it before it was retaken in 1918. This tomb is located in Mourmelon le Grand. Probably the father of one of the two older people in the photo? It could be fun to try and track down the kid, perhaps he remembers that day.