The leaders of France and New Zealand will lead a summit with representatives of major global technology companies in Paris Wednesday, as governments and Silicon Valley grapple with containing hate speech and incitement to violence on the internet.

French President Emmanuel Macron and New Zealand Prime Minister Jacinda Ardern called for the meeting after the March 15 Christchurch mosque shootings, in which 51 people were killed by a right-wing extremist who’d posted racist manifestos online and then live-streamed his rampage. Facebook Inc. and Alphabet Inc.’s YouTube were widely criticized for failing to quickly remove the video.

The Paris agenda also includes a push, dubbed the Christchurch Call, for attendees to make a pledge to curb the promotion of violent extremism on their platforms. The initiative isn’t legally binding and details will be disclosed after the meeting, Macron’s office said in a press briefing.

Twitter Chief Executive Officer Jack Dorsey, Facebook Vice President for Global Affairs and Communications Nick Clegg and Google Chief Legal Officer Kent Walker will attend the meeting, according to the French president’s office.

While not having Facebook Founder and CEO Mark Zuckerberg at the meeting is regrettable, “what’s fundamental is for Facebook to agree to this plan,” Ardern told Le Monde in an interview published Wednesday. “At the end of the day, everyone will be judged on their actions.”

Zuckerberg, who met with Macron in the French capital last week, was unable to return for the Wednesday meeting, an Elysee official said.

Attendees will also include Canadian Prime Minister Justin Trudeau, Irish Premier Leo Varadkar, British Prime Minister Theresa May and Jordan’s King Abdullah II, as well as representatives from Microsoft Corp. and Vivendi SA’s DailyMotion.