As Madrid becomes increasingly multicultural, especially in areas such as Lavapiés, visitors and residents of all nationalities are naturally accepted by what is in effect a fairly open-minded society. A person of a different race or skin color rarely draws more than a second glance, unlike a few decades back when a dark face was a rarity in a 99% Castizo city.
That said, instances of racial conflict are not unknown, though these tend to be with African, Arabic, and Latin American locals rather than multinational visitors (See "Health & Safety" for more information).
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.