Paris (AFP) - French police on Wednesday raided the headquarters of the company that published the works of Gabriel Matzneff, accused of raping a minor, as a date was set for his trial on a charge of justifying paedophilia.

The search at publishing company Gallimard's Paris offices was conducted by a police unit specialised in investigating violence against minors, a source close to the probe told AFP.

Investigators were looking for written passages that never appeared in any of Matzneff's published work, said the source.

Prosecutors on January 3 launched a rape investigation after a bombshell book by publisher Vanessa Springora claimed she had a sexual relationship with the author three decades ago, starting when she was 14.

In her book "Le Consentement" (Consent), Springora described how her seduction by Matzneff, now 83, left lasting scars.

Matzneff has never made any secret of his preference for sex with adolescent girls and boys, including on trips to Asia. In the mid-1970s, he published a notorious essay called "Les Moins de Seize Ans" (The under 16s).

In an interview in 2008, he said he had "self-censored" certain portions of his writings he feared would be judged "especially scandalous", and hid these away in a bank safe.

The safe had been "located" by investigators, according to the Mediapart investigative website.

Matzneff has long been tolerated, admired and even protected in Paris literary circles. In 2013, he won the prestigious Renaudot prize.

But Gallimard said in January it was halting the sale of his works, and Matzneff risks losing two major state honours as officer of Arts and Letters and knight of the Order of National Merit.

He said in an interview with French television in January that he "regrets" his trips to Asia to have sex with minors, claiming that at the time "no one ever said it was a crime".

On Tuesday, police launched an appeal for witnesses and victims to come forward in the case.

Confirming a Mediapart report, a source told AFP that investigators are also interested in Christian Giudicelli, Matzneff's editor at Gallimard and travel companion to the Philippines.

In a separate legal case, Matzneff will be tried on September 28, 2021, for "justification" of paedophile acts for statements he had made in the media in response to Springora's allegations.

Charges gainst him were brought by anti-paedophilia group l'Ange Bleu (Blue Angel). The hearing will be held at the Paris criminal court.