PARIS -- Real Madrid striker Karim Benzema was charged on Thursday with conspiracy to blackmail as part of an investigation over a sex tape involving France teammate Mathieu Valbuena.

Benzema also faced preliminary charges of participating in a criminal group in a scandal that has monopolised the national media's attention.

Few details of the case have been released, but investigators said they are trying to find out if Benzema played a role in an extortion attempt targeting Valbuena, and if he actually tried to blackmail the Lyon midfielder.

Benzema was handed the preliminary charges on Thursday after being brought before a judge at a Versailles court following a night spent in custody. The Real Madrid forward, who has been freed pending further investigation, faces a maximum prison sentence of five years, the prosecutor's office said.

In 2010, Benzema and another teammate on France's national team, Franck Ribery, were handed preliminary charges for soliciting an underage prostitute. Both were questioned and, three years later, acquitted.

Benzema's involvement in the sex tape case has yet to be determined, but investigators believe he was approached by a childhood friend to act as an intermediary between the blackmailers and Valbuena.

Karim Benzema has scored nine goals in 11 matches for club and country this season but is currently out injured. Victor Carretero/Real Madrid via Getty Images

"Karim Benzema will show his good faith in this matter as soon as possible," said Benzema's lawyer, Sylvain Cormier, adding that the charges arose from a question of interpretation. "He was charged by the judge who notified him that he was a suspect ... It is not a declaration of guilt."

Preliminary charges under French law mean magistrates have strong reason to believe a crime was committed, and allow time for further investigation. The charges may later be dropped.

Benzema was also placed under judicial supervision, meaning he cannot meet with the victim -- Valbuena -- or other people charged in the case. He can, however, continue to live abroad and travel freely, so Real Madrid should not be affected by the charges.

Benzema resumed light training with Real Madrid later Thursday.

Madrid said in a statement that club president Florentino Perez met with Benzema and showed his "full support" for the player and expressed his belief in the Frenchman's "innocence."

At least four other people have been handed preliminary charges in the case since October. The fourth was added Thursday evening, with the Versailles state prosecutor saying in a statement that the individual had also been placed in custody.

The investigation, which includes wiretap evidence, started this year when Valbuena decided to take legal action after being contacted by a man claiming to be in possession of an incriminating sex tape.

In the same case, former France international Djibril Cisse was briefly detained last month but released without seeing a judge.

Both Benzema and Valbuena play for France's national team. But because of the case, France coach Didier Deschamps won't be able to use both players at the same time while the investigation goes on.

With both men being key members of the national team, Benzema's judicial issues could also have an impact on France's performance at next year's European Championship, which France will host.

Deschamps left both players out of his squad for upcoming friendlies against Germany and England. Benzema is currently sidelined with an injury but Valbuena's omission was unexpected. Deschamps said the Lyon midfielder isn't in an emotional state to play in either game.

Deschamps was bombarded with questions related to the case at the start of his news conference but refused to take most of them.

"The best thing is to let the justice system do its job," Deschamps said.