Authorities blamed the violence on masked attackers from a libertarian group called the Black Blocs that numbered around 1,200 people in total and were on the margins of the 20,000-strong protest.

Several people, including a police service worker and a cameraman from Iranian state television IRIB, were injured. Collomb told France 2 Television he was pleased "no one was seriously injured."
[...]
Macron responded from Sydney: "There is a government. There is a state that's being run and it will continue to react."

Workers, students and others marched through cities around France during the May Day protests, aimed at expressing discontent over Macron's plans to overhaul some employee protections.