I thought you might be interested in some of the background story of the Plessy v. Ferguson case, which was overturned by Brown v. Board of Education in 1954.

On June 7, 1892, 30-year-old Homer Plessy was jailed for sitting in the "White" car of the East Louisiana Railroad. Plessy could easily pass for white but under Louisiana law, he was considered black despite his light complexion and therefore required to sit in the "Colored" car. He was a Creole of Color, a term used to refer to black persons in New Orleans who traced some of their ancestors to the French, Spanish, and Caribbean settlers of Louisiana before it became part of the United States. When Louisiana passed the Separate Car Act, legally segregating common carriers in 1892, a black civil rights organization decided to challenge the law in the courts. Plessy deliberately sat in the white section and identified himself as black. He was arrested and the case went all the way to the United States Supreme Court.

http://www.pbs.org/wnet/jimcrow/stories_events_plessy.html