Now, users who violate Facebook's "most serious policies" - such as sharing a link to statements from a known terrorist group - would be banned from broadcasting live videos on the platform for set periods of time.
The company says it will spend $7.5 million to partner with three universities to develop tools preventing modified versions of terror videos from being reposted.
The French and New Zealand governments drafted the agreement - a roadmap that aims to prevent similar abuses of the internet while insisting that any actions must preserve "the principles of a free, open and secure internet, without compromising human rights and fundamental freedoms". "Christchurch happened, and within days New Zealand acted to get weapons of war out of the consumer market".
The US has reportedly refused to sign up because of concerns about freedom of speech.
The Christchurch Call is a voluntary commitment by governments and tech companies to improve their efforts to tackle extremist content. It also blocked 1.2 million of them at upload, meaning they would not have been seen by users. The suspect, an Australian supremacist, had broadcast live vidoes of the attack for 17 minutes on the platform, which had subsequently gone viral on the social media platform.
"Although we deployed a number of techniques to eventually find these variants, including video and audio matching technology, we realised that this is an area where we need to invest in further research".
In response, Ardern, New Zealand's prime minister, has urged the tech giants to take more responsibility and ensure they "are not perverted as a tool for terrorism".
Signatories would "encourage media outlets to apply ethical standards when depicting terrorist events online, to avoid amplifying terrorist and violent extremist content", although the initiative is non-binding, light on details and leaves countries and companies to decide how to apply guidelines.
Significantly, tech companies have pledged to review their business models and take action to stop users being funnelled into extremist online rabbit holes that could lead to radicalisation.
But in a blow to the strength of the mandate, the United States has chosen not to sign despite extensive diplomatic efforts and the fact that a representative was in Paris at a parallel meeting of G7 Digital Ministers. They include making it easier for users to flag up inappropriate content, using enhanced vetting for livestreaming and publishing transparency reports on material that's removed.
The social media giant made the announcement today ahead of a meeting of world leaders aimed at curbing online violence in the aftermath of the mosque killings in New Zealand.