With most sets of stereographic images, you can get a sense of what's going on from the captions, action, provenance - all sorts of things. Here, I'm more or less at a loss - but the stereoviews are pretty darn cool!
An amateur set of contemporary modern ruins photography of Reims, at and around the bombed-then-burned-out Cathedral, and probably taken well before the end of the Great War, shows 12 views from a very talented photographer, documenting the damage to a beautiful city and its centerpiece.
An amateur set containing 7 views from the Great War: 3 of an ambulance convoy leaving to pick up the wounded of Champagne, 3 of a convoy at Saint-Mesmes, and one of soldiers camped in a small village (probably the latter).
In which we look at 11 slides from the second box of the Puthon Collection, get into some more rugged mountaineering, sit at a picnic table with a telescope looking over Mont Blanc, and more!
4 "digital prints" from negatives of life in the camp of the 36th Artillery Regiment stationed in Saint Airy Forest at Verdun in January 1918 show snowbound soldiers near one's shelter - as well as a peek into the shelter itself!
Four of A. O. Fasser's stereo photos (from a set on Belgium) are not like the other ones - let's take a look!
Marketed as the collection of a French Artillery Sergeant's personal photography before, during, and after the Great War, I was sold a disparate collection of mostly-junk by an eBayer who didn't know what he was talking about. Here's the story, and one of the few slides that likely had anything to do with the Great War.