Correction: 5/6/2017: A previous version of this story (May 2, 2017) said French police carried and used "hand grenades". The grenades were non-lethal tear-gas grenades.

Paris, France - With less than one week to go until Sunday's presidential election, tensions were high as tens of thousands of people took to the streets of Paris on International Workers' Day, or May Day.

Various groups protested against racism, capitalism, police brutality, the far-right presidential candidate Marine Le Pen and her frontrunner rival, centrist Emmanuel Macron, and called for workers' rights and social equality.

Police in their hundreds, decked out in riot gear and armed with tear-gas canisters, tear-gas grenades and batons, travelled in vans with sirens hours ahead of the march to the Place de la Republique.

Undocumented migrants, mostly from sub-Saharan Africa, demanded an end to deportations.

Meanwhile, trade unionists called for greater workers' rights and anti-Le Pen activists called on people to vote against the far right.

"We want to show that left-wing citizens are mobilising against the National Front [FN], and that we are not merely bystanders," an anti-Le Pen organiser told Al Jazeera.

"Le Pen wants people to believe that she is going to protect the weakest while [she is instead] reinforcing inequality and creating a hierarchy of poverty."

On April 23, Le Pen, a Eurosceptic, came second in the first round of the presidential election, winning 21.4 percent of the vote.

Emmanuel Macron, a pro-EU centrist, won 23.9 - meaning the rivals will compete for France's top job on May 7.

"A lot of extreme right groups in Europe are watching this election," Mohamed Slemani, an activist, told Al Jazeera.

"If Le Pen wins the presidency, it's the end of EU. I was in Rome last week and saw pro-Le Pen posters."

Disenchanted with Macron's politics, he said that he was undecided how to vote on Sunday.

He said he was also disillusioned with some elements of the left, explaining that they do not prioritise Islamophobia.

There are between 5.5 million and 6.2 million Muslims in France, or roughly 7.6 percent of the total population - making the group the largest Muslim minority in Europe.

The community often comes under attack as many conflate Islam with "terrorism".

Slemani said the first victims of Islamophobia are women who are visibly Muslim.

"If Le Pen wins, Muslim women will be the first target," he said, suggesting that activists must build networks to combat all forms of social inequality.

During Monday's rally, several other political, activist and underground groups gathered under various banners, from the Marxist-Leninist Communist Party of Turkey and pro-Palestinians, to the trade unionist CFDT and UNSA organisations and the losing leftist candidate Jean-Luc Melenchon with his Unsubmissive France party.

Several people said they were likely to vote for Macron in a bid to stop a Le Pen presidency, but some had reservations about their decision.

"First of all, I'm here to defend workers' rights," Diego Berjer, a 19-year-old student, told Al Jazeera.

"The second reason is because of the political context. It's important to demonstrate against Le Pen. I will never enter dialogue with people who are racist and fascist.

"Unfortunately, against my heart, I will vote for him [Macron] on Sunday. I don’t like his neoliberal policies. He’s a repulsive person."

Mathurine, who works in insurance, said she came out to protest against the FN and Le Pen.

"I'm black, I don't want her to take power. Racism is a big problem in France. If she becomes president, we will have a civil war," Mathurine said.

"There's a high level of unemployment and Le Pen made a link between joblessness and foreigners. She also played on the issue of terrorism. I'm not for Macron, but to fight against Marine [Le Pen], I'm going to vote for Macron."

Others said they would consider abstaining in Sunday's vote.

"I’m against fascism," said Alain Biaros, a film director. "I wanted to abstain, but if there is some danger [of a Le Pen win], I will vote for Macron [but] I don’t like his policy. He's a candidate of the banks."

Thomas, a musician, wore a homemade cardboard placard announcing he would abstain.

"Macron has implemented policies that make workers' lives more precarious," he said. "I won’t fall for this blackmail."

The rally began peacefully in the early afternoon with a festive atmosphere.

Later in the day, clashes erupted as police fired tear gas and used tear-gas grenades on anti-fascists and other demonstrators.

Al Jazeera saw several protesters injured in the violence, while images posted on social media showed a number of police also wounded.

A witness, who requested to remain anonymous, said: "At the head of the march, police charged the demonstration and surrounded a group of around 200 to 300 young demonstrators who were predominantly dressed in black. I didn't see any action or any violence that could have justified the violence of the police."

One photographer, who was bleeding from the head, told Al Jazeera that a tear-gas canister struck him.

With additional reporting by Naima Bouteldja