An elderly French man has been charged with the rape and sexual assault of 89 teenagers in a mass abuse case that police allege spans many countries and dates back to the 1960s.

Jacques Leveugle, 79, who is in custody in south-east France, was arrested after his nephew found a USB that allegedly detailed his "sexual relations" with minors aged 13 to 17, the Grenoble prosecutor, Etienne Manteaux, told a news conference.

In an unusual move, authorities are naming the suspect because out of the 89 assaults, Manteaux said that only around 40 victims had been identified.

"If victims wish to come forward, now is the time," he added.

Police allege the crimes took place between 1967 and 2022.