FFF: Ribery & Govou innocent for now
Lawyers for the two France internationals said Ribery and Govou had already been questioned and a police source close to the investigation said a third player should follow.
"The FFF wishes to state its attachment to the presumption of innocence principle and express its faith in the judicial process," the organisation said in a brief statement.
"The FFF has no access to the case's file and will make no further statement until the judicial process comes to a conclusion."
French media said players heard by investigators were clients of a nightclub in Paris's posh Champs-Elysees district that allegedly featured escort girls.
Ribery and Govou play for Bayern Munich and Olympique Lyon respectively and could face each other in the first leg of the Champions League semi-final in Germany on Wednesday.
Lyon chairman Jean-Michel Aulas told reporters in Munich he had complete confidence in Govou.
"Sidney came to see me in my office before the team left Lyon for Munich on Monday and his explanations were convincing," said Aulas.
"His lawyer has confirmed he was not involved and, obviously, I'm absolutely ready to believe him," he added.
France playmaker Ribery was scheduled to appear at a news conference in Munich on Tuesday but was replaced by defender Philipp Lahm as Bayern declined to discuss the police probe.
Les Bleus, preparing for the World Cup in South Africa in June, could have done without all this.
The former world and European champions have faced criticism for under-performing since reaching the final of the last World Cup four years ago in Germany.
Ribery is France's most popular player since Zinedine Zidane, who retired after his infamous headbutt in the defeat by Italy on penalties in the 2006 World Cup final.