Ribery and France forward Sidney Govou have already been questioned and another player should follow, a police source close to the investigation told Reuters.
"Personalities including Franck Ribery and other players of international fame count in their relations a person close to the leader of an escort girls network," Ribery's lawyer, Sophie Bottai, said in a statement.
"It is only because of that relationship that they have been or will be heard by police investigating this case," she added.
Govou's lawyer, Thierry Braillard, said his player "was not involved in the case, neither directly nor indirectly." The player's club, Olympique Lyon, said in a statement they fully supported him.
French media said players heard by investigators were clients of a nightclub in Paris's posh Champs-Elysees district that allegedly featured escort girls.
The French Football Federation (FFF) declined to comment on the reports, which got prominent play in some French newspapers on Monday.
France, preparing for the June 11-July 11 World Cup finals in South Africa, could have done without all this.
The former world and European champions have faced criticism for under-performing ever since reaching the final of the last World Cup four years ago in Germany.
Their coach, the uncompromising Raymond Domenech, is extremely unpopular and booed at every game and, to make matters worse, France needed a goal marred by a blatant handball from Thierry Henry to knock out Ireland in a playoff for the finals.
Ribery, usually energetic on the pitch and unassuming off it, is probably the most popular player in the squad.
