France international striker Karim Benzema went on trial on Wednesday in absentia charged with complicity in the attempted blackmail of his former international teammate Mathieu Valbuena.
Benzema, 33, has denied wrongdoing in what has become known as the 'sex tape' case.
Prosecutors say the Real Madrid forward encouraged Valbuena to pay a suspected group of blackmailers in order to keep a sexually explicit videotape out of the public eye.
Benzema played in Madrid's 5-0 win in Ukraine over Shakhtar Donetsk on Tuesday night in the Champions League. His lawyers said he was unable to attend the hearing in Versailles, near Paris, due to professional reasons.
Prosecutors say Valbuena received a first call threatening to expose the tape in June 2015 while he was at the French squad's training centre in Clairefontaine, west of Paris.
The contact came soon after Valbuena had handed his smartphone to Axel Angot with the request to transfer its contents to a new device.
Angot, who is on trial for breach of trust, came across sexually explicit footage on the phone involving Valbuena.
Prosecutors say he then explored ways - together with a friend, Mustapha Zouaoui - to approach Valbuena and threaten publication of the footage unless he paid them.
The blackmailers then went to the former France international Djibril Cissé, who refused to act as their messenger. He warned Valbuena of what was brewing.
"Initially, I didn't believe it, I thought they were bluffing," Valbuena told the court on Wednesday.
He said Cissé, who had himself been the victim of a similar blackmail attempt, described to him the contents of the video, an extract of which he had received via WhatsApp.
"I felt in danger," Valbuena told the hearing. "My first reflex was to file a criminal complaint. I feared for my sporting career and for the French team.
"I knew if the video came out things would be difficult for me in the French team, as was proven to be the case later."
Both Valbuena and Benzema lost their places in the national squad though Benzema was restored to the fold just before last summer's European championships.
An undercover police officer posed on Valbuena's behalf as a middleman and recorded phone conversations between June and October, 2015 that helped identify the alleged blackmailers, according to prosecutors.
Benzema was recruited by the alleged blackmailers to encourage Valbuena to pay as his teammate stalled, they claim.
Angot, Zouaoui, Karim Zenati and Youness Houass, are being tried on charges of attempted blackmail.
The hearing continues.