French riot police fired tear gas at activists protesting as part of global climate demonstrations Sunday, on the eve of the COP21 climate summit in Paris.
About 200 protesters, some wearing masks, fought with police on a street leading to the Place de la Republique, which has become a gathering place for Parisians since the terror attacks on Nov. 13.
By late afternoon, about 100 people had been arrested during the protests in Paris, according to French police, who said the clashes remained tense but no injuries had been reported.
More than 2,100 events worldwide were planned for the Global Climate March, which organizers say is one of the largest climate change protests in history.
But demonstrators in France were warned not to gather amid the state of emergency enacted after the Paris attacks. French police told NBC News that some 4,500 people formed a human chain around midday.
Video on social media showed armored police dispersing the crowd and canisters of tear gas being deployed.
Using the state of emergency rules, police put 24 green activists under house arrest ahead of the summit saying they were suspected of planning violent protests.
Thousands of shoes — including a pair from the pope — were arranged at the Place de la Republique to represent activists who could not participate due to the ban on large gatherings. Organizers said they had collected more than 11,000 pairs of shoes.
Elsewhere, the rallies appeared to be peaceful. More than 50 major marches were planned around the globe, with some events held on Friday and Saturday.
In Australia, organizer Reece Proudfoot said 130,000 people participated in rallies, according to Sydney Morning Herald. Sydney's mayor tweeted that 45,000 people attended the city's march, making it the largest in the city's history. Protesters held placards reading: "There is no Planet B," and "Say no to burning national forests for electricity."
In London, protesters who marched from Hyde Park to the Whitehall government district were joined by actress Emma Thompson, designer Vivienne Westwood and Labour Party leader Jeremy Corbyn.
"This is our planet and we are in deep, grave danger," Thompson told Sky television.
U.S. president Barack Obama and his Chinese counterpart, Xi Jinping, will be among more than 140 world leaders in Paris for the COP21 summit.
Security for the talks has been stepped up in the wake of the Paris terror attacks. Negotiators from 196 countries are hoping to hammer out a long-term deal to curb global warming during the conference, which will take place between Nov. 30 and Dec 11.