It is not abnormal to be fascinated by ruins – in point of fact, I make a living trotting about inside abandoned buildings and taking photographs. Plenty of people did so after the Great War, as France and Belgium were rebuilding everything destroyed by their enemies. Therefore, it is rather difficult to date these images – being that they could have been taken after Armistice, after the bombardment, etc.
I would suggest that the presence of the (presumably) tourist couple’s car would date it to the postwar period. Unless the stickers were affixed after the Armistice, there would be no way of knowing that the war would be over in 1918.
There is a lone figure in most of the ten photos contained in the unlabeled diapositive box, and no contextual clues other than the captions affixed to the slides with a seemingly common sort of sticker in between the images on each. The figure is that of a woman – rigid, with a stony expression, standing amidst the wreckage of war, and in one case leaning against their car (the number plate,” 3470-E”, is the same near the Cathedral and near what was left after the French Revolution of the Abbey). With no other people in frame, even with vast expanses of the commune visible, she takes on a ghoulish appearance. So without further ado, meet the Ghoul of Soissons: