A protester kicks back a tear gas canister during a demonstration in Marseille, southern France, on October 17.

Tens of thousands of people are expected to take to the streets across France today as part of student protests that have been ongoing for nearly a month.

Here’s what we know about today’s demonstrations so far:

Protests began in cities across France this morning local time, in places including Rennes, Lyon, Marseille and Paris.

In the French capital, hundreds of people gathered at Place de la République, where today’s main march is expected to begin. Things escalated quickly, with police deploying tear gas in the square and charging into the crowd. A small group of protestors aimed fireworks at police lines.

Police in Lyon also launched tear gas grenades to disperse around 300 people who had mobilized outside the city’s Jean Moulin University, according to CNN’s French affiliate BFMTV.

Today’s march in Paris was scheduled to begin at 2:30 p.m. local time (8:30 a.m. ET), according to CNN affiliate BFMTV.

France’s Interior Ministry will also be holding a crisis unit meeting at 6 p.m. this evening (12 p.m. ET), BFMTV reported, citing sources.

The chiefs of staff for the Prime Minister, the Interior Minister, and the Minister of Justice will be in attendance, it reported.

Though the recent protests in France were started by students, people from different walks of life and across the political spectrum are expected to attend today’s demonstrations.

Jean-Luc Mélenchon’s far-left La France Insoumise has backed the student movement and is expected to show up at demonstrations in support of the protesters and their demands.

Some farmers have discussed staging tractor protests, while taxi drivers have already begun staging rolling roadblocks and blockades around Paris airports and say they intend to continue through Saturday.

The gilets jaunes, or Yellow Vests, have also been present at demonstrations today.

Speaking last night about today’s planned protests, French President Emmanuel Macron asked for “calm.”

“There is a constitutional right to protest, but what goes along with this right is respect,” Macron said.

The Paris Police Prefecture, the body that oversees the Paris Police Force, emergency services and various other administrative departments, has defended the actions of its officers and criticized “hostile” demonstrators.

“We do not back down in the face of rioters and those who’ve come to attack law enforcement,” the supervising unit said in a post on social media earlier today.

CNN’s Joseph Ataman, Elina Baudier Kim and Charlotte Reck contributed to this reporting.