Riot police have fired tear gas into crowds of protesters at the Place de la Republique in Paris and arrested as many as 100 people ahead of critical global warming talks to be held outside the city on Monday, reported The Independent.

The activists were gathered on the eve of a huge United Nations climate conference, which will bring together leaders from across the world.

France has been placed under a state of emergency since coordinated attacks in the capital city that killed 130 people.

According to the BBC, “There were flares being set off, and at one point there were a couple of loud bangs, and shortly after that one group of riot police started running towards the protestors…

“The protestors were mainly French, all the signs were in French, they looked like French political protestors. It looked like there were hundreds, rather than thousands.”

In Australia, more than 45,000 people marched through the streets of Sydney on the eve of the climate summit, reported Al Jazeera. Earlier, more than 50,000 had marched and rallied at events in Melbourne, Brisbane, Canberra and elsewhere.

On Sunday morning in India, more than 5,000 residents of New Delhi participated in a meditation session and listened to musicians sing songs dedicated to the earth as part of events to highlight the need for an agreement at the climate summit.

Police in Berlin said they were expecting 15,000 people to take part in the Global Climate March in the German capital, which began at 11:00 GMT.

Back in Paris, French President Francois Hollande was expected to hold a series of meetings on Sunday with UN Secretary General Ban Ki-Moon, Canadian Prime Minister Justin Trudeau and Chinese President Xi Jinping.

According to NPR, “At an artists’ workshop on the outskirts of Paris, organizer David Solnit says besides hampering public events, police are using the state of emergency invoked after this month’s terror attacks to target environmentalists.

“‘There’re people being stopped on the street, I mean, we’re basically in an authoritarian police state,’ he said. “And the French government is particularly targeting activists.

“With the climate conference set to begin, France’s interior minister says some two dozen green activists are under house arrest.”

Earth’s temperature is currently on course to rise at least four degrees this century as a result of increasing amounts of carbon dioxide and other greenhouse gasses in the atmosphere.