Were people of mixed race, black and white, treated the same? Or worse because they were black but had white in them?
Could you be more specific? Do you have a time period and place in mind?
I recommend reading Life On the Color Line by Gregory Howard Williams. It's a true story about a boy who was raised white until his mother died. He and his father moved back to Indiana to be with family- his fathers family was black, though he didn't know it before. This all occurs in the 1950s and does well to discuss how a person of mixed race deals with both sides.