The police statement recorded that the woman was attacked in a toilet in a nightclub near Piazza Navona, a square popular with tourists in the historic centre of the city.
Italian media said the incident took place on Monday night.
Police are yet to reveal the identity of the player or his victim, a student in Rome.
Local media said the Frenchman was in Italy to try out for a local club.
Two Serie A teams are based in the capital — league leaders AS Roma and Lazio.