Rafael Nadal has won the most number of singles title at French Open.
Bjorn Borg was the Men's Singles Champion at the French Open in each year between 1978 and 1981.
Arantxa Sánchez Vicario (Spain).
Bjorn Borg has won the French Open 6 times (1974-75, 1978-81). This does not include the time period before 1968, when the tournament was referred to as the French Championships. The French Championships were not "Open" to players that were not members of french tennis clubs or french nationals.
Jennifer Capriati was the women's singles champion at the French Open in 2001.