The windows are surrounded with concrete hoods. Below the windows are embedded gray colored stones also surrounded same concrete hoods.
I would use an off-white cream color that fits nicely with the gray color. This would be a simple approach, but if done right would allow it to be classy combination that would attract people to it.
Beige or yellow should work well, which one you choose depends on the shade of brown of the roof. A darker brown roof would require a beige paint to match it while lighter browns would work better with yellow. Both colors will match with the concrete hoods and gray stones, so choose the one which best matches the roof.