Paris - The stepson of a renowned French professor and political commentator has filed a complaint against him with prosecutors for alleged incest, in a case that has shaken France and prompted a review of legislation.
Under French law, incest is sexual abuse by any relation, even if they are not related by blood.
The accusations against Olivier Duhamel first surfaced in a book written by his stepdaughter Camille Kouchner, sister of the alleged victim.
The case has led hundreds of people to share their stories of incest on social media and French President Emmanuel Macron said at the weekend that France would tighten its laws on incest and seek to better protect children.
"The presumed victim ... has filed a complaint against his former stepfather Olivier Duhamel following the opening of a preliminary investigation by the Paris prosecutor," lawyer Jacqueline Laffont said in a statement.
Duhamel's lawyer did not immediately respond to a request for comment.
Duhamel resigned this month from his post overseeing Sciences Po, one of France's top universities, after the book was published.
He said he had resigned after "being the object of personal attacks", but neither he nor his lawyer have commented on the accusations, which relate to events dating back to the 1980s.
Macron said on Saturday that he had asked the justice minister to chair a consultation aimed at quickly making legislative proposals.