Painting Walthers Hardwood Furniture

I’m getting ready to build Walthers Hardwood Furniture and would appreicate some advice on how to fini***he walls. They appear to be either “stone” or concrete and I’m not sure what color(s) they should be. The model will be in the foreground.
Thanks

I would recomend doing it in a lighter gray and depending on era modeled, a wash of india ink and alcohol