The probe was launched after the examination of the book “Consent” by Vanessa Springora, published on Thursday, where she describes a sexual relationship she had with Matzneff when he was 36 years her senior, Paris prosecutor Remy Heitz said in a statement.
Heitz said that the probe would be into “rapes committed against a minor” aged under 15.
In “Consent”, Springora, 47, now a leading publisher, describes how she was seduced at the age of 14 by Matzneff and how this left lasting scars.
Matzneff never made any secret of his preference for sex with adolescent girls and boys. In the mid-1970s, he published a notorious essay called “Les Moins de Seize Ans” (“Those Less than 16”).
Heitz said that even beyond the events described by Springora, the investigation “will work to identify all other eventual victims who could have been the victims of crimes of the same nature in France or abroad”.
Springora had indicated she did not intend to bring a criminal complaint against Matzneff. But the Paris prosecutors used their power to open an investigation of their own accord.
The book's publication on Thursday came as France is coming to terms in the age of #MeToo with a settling of scores after decades of what is seen by some, but not all, as an overly permissive attitude towards sexual exploitation of women and paedophilia.
In one of the most prominent recent cases, French actress Adele Haenel accused film director Christophe Ruggia of constantly harassing her from the age of 12 to 15. She has since filed a complaint against him.
And the controversy has intensified around French-Polish film director Roman Polanski, a fugitive from US justice since 1978 after admitting to statutory rape of a 13 year-old, after he brought out his new film “An Officer and a Spy”.
Matzneff has denied any wrongdoing and in a statement to the Parisien newspaper on Sunday denounced “such unjust and excessive attacks,” claiming that his relationship with Springora had been one of “beauty”.