The Nice French Riviera Open was an ATP World Tour 250 series and, formerly, Grand Prix tennis circuit affiliated men's tennis tournament. This tournament was originally founded in 1925 as a combined event called the City of Nice Championships and remained as a combined event until 1971 and 1976 to 1978. Also known as the Nice International Championships. It was held in Nice, France at the Nice Lawn Tennis Club and played on outdoor clay courts. The last singles champion is Dominic Thiem from Austria.