Brussels (AFP) - French President Francois Hollande on Sunday condemned the "scandalous" behaviour of far-left activists who clashed with riot police in an area dedicated for memorials to the Paris attacks ahead of key UN climate talks.

Around 100 people were arrested after a small group of protesters at the central Place de la Republique square pelted officers with bottles as well as candles that had been left in tribute to the victims of the November 13 attacks.

"These disruptive elements have nothing to do with defenders of the environment," Hollande said at an EU-Turkey summit in Brussels.

"They are not there so that the (COP21) talks succeed but are there solely to create incidents," he said.

"It is doubly regrettable, even scandalous that this happened at the Place de la Republique where flowers and candles have been left in memory of those who were killed by the terrorists' bullets" in the November 13 Paris attacks, he said.

He said it was also regrettable "in relation to the climate conference which will allow the world to decide the future of the planet."

Around 4,500 activists had earlier linked hands in the French capital in a peaceful protest pleading for leaders to curb global warming.

France has banned all demonstrations, including those for the climate talks, in the wake of the November 13 atrocities which left 130 people dead.