An NGO filed a case against a Saudi general in a Paris court on Friday, accusing him of being responsible for the torture of journalist Jamal Khashoggi in 2018, its lawyer said.

Khashoggi was tortured, killed and dismembered inside the Saudi consulate in Istanbul after going there to get documents for his wedding.

The Gulf Centre for Human rights (GCHR) holds General Ahmad al-Assiri, a former intelligence official,  responsible for the "physical and psychological abuse" that Khashoggi suffered just before his death, the NGO's lawyer William Bourdon said.

French courts have universal jurisdiction over crimes of torture, but not in murder cases, which is why the GCHR suit focuses on the torture claim and not the subsequent killing of Khashoggi, Bourdon told AFP.

In February, the US imposed sanctions on Assiri as well as an elite Saudi unit for their role in the killing.

The Treasury Department said it would block assets and criminalise transactions with the Rapid Intervention Force, which a declassified intelligence report said was answerable to Crown Prince Mohammed bin Salman, as well as al-Assiri.

The French complaint lodged Friday says Assiri was "the organiser and the planner of the mission which led to the torture and then to the murder of the journalist", according to files seen by AFP.

Assiri, part of the crown prince's inner circle, was exonerated in a closed-door trial in Saudi Arabia that was sharply criticised by rights groups.

The 59-year-old Khashoggi was strangled and had his body cut into pieces by a 15-man Saudi squad inside the Istanbul consulate, according to Turkish officials. His remains have not been found.  

A Saudi court sentenced 11 unidentified defendants in December 2019 for the killing after international pressure.

"France has a strong obligation to capture those who are suspected of acts of torture if they are on our territory," Bourdon said, adding that Assiri "is probably in France now, or at least comes here regularly".

The general, who speaks French and once studied at France's Saint-Cyr military academy, "is a regular at the defence ministry where he has his contacts", Bourdon said.

GCHR, based in Lebanon, provides support and protection to human rights defenders in the Gulf region and neighbouring countries.

The Saudi embassy in Paris could not immediately be reached for comment.