India, May 16 -- The leaders of France and New Zealand joined with the world's biggest online platforms in pledging to help curb the internet's role in spreading hate speech and incitement to violence.

At a summit in Paris Wednesday, representatives from Facebook Inc., Twitter Inc. and Alphabet Inc., committed to use and develop rules, algorithms and direct intervention to curb the uploading, promotion, amplification and distribution of violent extremism on social media platforms. The initiative calls for hate speech to be "immediately and permanently" taken down, though isn't legally binding.

French President Emmanuel Macron and New Zealand Prime Minister Jacinda Ardern, were joined by leaders from the U.K., Canada, Jordan, Indonesia a...