One of the main groups representing Muslims in France said on Monday it was suing Facebook and YouTube, accusing them of inciting violence by allowing the streaming of footage of the Christchurch massacre on their platforms.
The French Council of the Muslim Faith (CFCM) said the companies had disseminated material that encouraged terrorism and harmed the dignity of human beings. There was no immediate comment from either company.
The shooting at two mosques in New Zealand on March 15, which killed 50 people, was live-streamed on Facebook for 17 minutes and then copied and shared on social media sites across the internet.
Facebook said it raced to remove hundreds of thousands of copies.
However, the footage could still be found on Facebook, Twitter and Alphabet Inc's YouTube a few hours after the attack, as well as Facebook-owned Instagram and Whatsapp.
Abdallah Zekri, president of the CFCM's Islamophobia monitoring unit, said the organisation had launched a formal legal complaint against Facebook and YouTube in France.
Both companies have faced widespread criticism over the footage.
The chair of the U.S. House Committee on Homeland Security wrote a letter to top executives of four major technology companies last week urging them to do a better job of removing violent political content.
A spokesman for the Federation of Islamic Associations of New Zealand (FIANZ) welcomed the French group's action. He said his organisation had been planning to contact Facebook to register their complaint but had been busy dealing with the aftermath of the attacks.
"They have failed big time, this was a person who was looking for an audience and ... you were the platform he chose to advertise himself and his heinous crime," said FIANZ spokesman Anwar Ghani, referring to Facebook.
"We haven't been in touch with the (French) group ... but certainly, something which can deter the social media space in terms of these types of crimes, we would be supportive of that," he said.
A man has been charged with one count of murder over the Christchurch shootings and will next appear in court on April 5.