HERE is a light color wainscotting with dark wall, and HERE is the opposite. The light color wainscotting seems to be much more common with most dark wainscotting being natural wood. You could pull a color from the wallpaper for the wainscotting, or you could use a neutral beige, taupe, or gray of any shade. I would need to see the wallpaper to give you my opinion.

We need pictures beige can be almost any color and some idea of the space would be nice.