At least one player tested positive for a banned stimulant at this year's French Open, the French sports daily L'Equipe reported on Friday.
In an unsourced report L'Equipe said at least one of the 152 samples tested during the tournament had been positive.
Tournament organisers said they were unaware of a positive test and the International Tennis Federation said they would not comment on a potential case until the full process was concluded.
L'Equipe said the player faces a two-year ban unless there were mitigating circumstances.