What claim did plessy make to Louisiana state Supreme Court?

Homer Plessy claimed that Louisiana's Separate Car Act, which mandated racial segregation on public trains, violated his rights under the Thirteenth and Fourteenth Amendments of the U.S. Constitution. He argued that the law enforced racial discrimination and denied him equal protection under the law. Plessy's case ultimately led to the landmark Supreme Court decision in Plessy v. Ferguson (1896), which upheld the constitutionality of racial segregation under the "separate but equal" doctrine.