Four people, including former France international Djibril Cisse, have been taken into custody in France as part of an investigation into an alleged blackmail attempt.
AFP news agency, citing an unnamed police source, said the case concerns a suspected attempt to blackmail France international Mathieu Valbuena over an alleged sex tape.
According to a police statement quoted in Le Parisien, Cisse, 34, was detained by judiciary police in Versailles outside Paris. He was later released without appearing before a judge.
The statement read: "Djibril Cisse was taken into custody by members of the regional directorate of the judiciary police of Versailles as part of a criminal investigation opened at Versailles regional court on July 31, 2015."
The statement also said the investigation targeted blackmailers suspected of being involved in a criminal conspiracy "with a view to preparing a crime punishable by at least five years' imprisonment."
Versailles prosecutor's office also confirmed that three other people were put in custody on Tuesday morning, but a prosecutor's spokeswoman said the identity of the victim would not be revealed officially "out of respect for his/her private life."
Sources close to the case told AFP that the four were taken into custody on Tuesday morning following "an attempt to extort money" from Valbuena, 31, allegedly by claiming to have a "sex tape" he featured in.
In spite of the unfolding story, Valbuena was pictured training as normal for Lyon on Tuesday. Contacted by AFP, the France winger's lawyers said that neither they nor their client wanted to make any comment in order to help ensure that proceedings run smoothly.
One other person was detained in the north of the country, while two were picked up in Marseille. According to French TV channel I Tele, between €50,000-100,000 was demanded from Valbuena, although it is said that no money changed hands. Police in Versailles are leading the investigation.
Valbuena and Cisse played together at Marseille between 2006 and 2009 and were also part of the French squad for the 2010 World Cup.
Le Parisien reported that Cisse was himself the victim of a similar attempt at blackmail in 2008. According to the paper, the ex-Auxerre, Panathinaikos and Lazio player is said to have received phone calls from someone demanding €150,000 be paid in order to stop an intimate video being released on the internet.
Cisse reportedly gave in to the blackmailer, who was arrested for shoplifting two weeks later and had a cheque for €9,000 which had been signed by the player.
Valbuena left Marseille after eight seasons at the club to join Dynamo Moscow last year before returning to his homeland to sign for Lyon this summer.
Last season Cisse featured as a substitute in eight league matches for Bastia before his contract expired in the summer. In September, Cisse prematurely ended a short-term deal with a club in the French overseas department of Reunion.
He blamed injury for his decision to leave the Indian Ocean island in order to return to France.
Information from The Associated Press was used in this report.