The clay courts at the French Open are red.
The familiar color comes mainly from a thin layer of powdered red brick spread over the playing surface. At Roland Garros, the courts are not simply made from natural clay: beneath the brick dust are layers including white limestone, volcanic rock, sand and concrete. The red covering gives the tournament its instantly recognizable appearance.
This surface also affects how tennis is played. Clay is slower than grass or hard courts, and the ball generally bounces higher. The surface can reduce the advantage of powerful serving and reward players who construct long points, defend effectively and use heavy topspin. Ball marks remain visible after a bounce, allowing officials to inspect close calls.
The French Open has been the only Grand Slam tournament played on clay since the US Open changed to hard courts in 1978. A common mix-up is calling the courts simply “orange”; they are conventionally described as red clay, even though the exact shade can vary with moisture, lighting and court maintenance.