Riot police have fired tear gas at far-left activists in Paris during a climate change demonstration ahead of key UN talks in the city, with around 100 people arrested.
Authorities moved in after a small group of protesters pelted officers with bottles and candles from one of the tributes to the victims of the November 13 attacks on the French capital.
Around 4500 activists had earlier linked hands in a peaceful protest near the site of the deadliest of the attacks, pleading for leaders to curb global warming.
Hostilities began as activists were warned there would be a zero tolerance approach to protests, given Paris was still under a state of emergency.
The colourful human chain passed near the Bataclan concert hall where 90 people were killed in the suicide bombings and shootings.
Stretching for two kilometres along a wind-blown Boulevard Voltaire in eastern Paris, it was the first organised demonstration since the attacks claimed by the Islamic State in which 130 people died and hundreds were injured.
“Hear our voices! We are here!” cried the demonstrators ahead of the 195-nation UN summit being held just outside Paris, which aims to strike the first truly global accord to limit greenhouse emissions and avert a global climate disaster.
But around two hours after the human chain dispersed, anti-capitalist militants who had gathered in the nearby Place de la Republique square that has become a rallying point for mourners after the attacks began to clash with police, AFP reporters said.
A group of militants wearing black hoods and scarves over their faces chanted “State of emergency, police state, you will not take away our right to protest”, referring to the measures restricting demonstrations that were introduced after the attacks.
As objects were thrown, police in riot gear formed lines to push them back and the air was filled with tear gas.
French authorities have had to strike a delicate balancing act for the climate demonstrations.
Activists organised the human chain in place of a march that was banned for security reasons after the attacks.
Dozens of French climate activists have been placed under house arrest to prevent them from demonstrating in Paris, angering their lawyers who claim the state of emergency powers are being abused.