I'm stationed here in germany and from what I can tell, almost all the cobblestones where cars drive are like a black shaleish color, and the others like the sidewalks or other routs are like a rough grayish type of rock and the older cobblestones are breaking away to reveil like a sandstone looking rock under the cookie like stones.
as far as the houses, the ones that didn't get blown apart are a fadded earthy color of brown, yellow, cream white, or some other softer color. Most of the newer houses are a brighter more vibrant shade of just about any color.
I have some pictures up on ron georges site if you want to look at a few, I also have a few of Kosovo which might give you an idea of what europe could've looked like in WWII?