Since July, prosecutors have been investigating a plot to blackmail the Lyon midfielder Mathieu Valbuena.
Mr Benzema, who has played 81 matches for France, was arrested by appointment at a police station in Versailles earlier. The Versailles prosecutor has placed him under formal criminal investigation.
An anonymous police source, quoted by the news agency Reuters, said the striker’s name came up during phone taps conducted by investigating officers.
Mr Benzema hid behind a white hoodie as he arrived at the police station this morning. It is not known how long he will be questioned.