I recently stumbled across a French museum site which appears to have the original art for many of the Epinal models dealing with WWI. Here, for example, is the watercolor for the Zeppelins Over Paris.
The artwork is credited to Louis Georges Albert Morinet. It's interesting to see how much more subtle the coloring is in these originals than in the final models done with fewer colors and stencils. One other notable difference is where there are reversed figures Morinet has rendered them only in gray watercolor.
There are quite a few more, including some models I've never seen the finished versions of. My apologies if
this site is already known to all y'all.