France's Senate voted late Saturday to approve a deeply unpopular reform to the country's pension system, hours after demonstrators took to the streets to oppose the cornerstone policy of President Emmanuel Macron's second term in office.

Senators passed the reforms by 195 votes to 112, bringing the package another step closer to becoming law.

A committee will now hammer out a final draft, which will then be submitted to both the Senate and National Assembly for a final vote.

"An important step was taken this evening with a broad vote on the pension reform text in the Senate," Prime Minister Elisabeth Borne told AFP after the vote, adding that she believed the government had a parliamentary majority to get the reforms passed into law.

Should Macron's government fail to assemble the necessary majority, however, Borne could deploy a rarely used and highly controversial constitutional tool, known as article 49/3, to push the legislation through without a vote.

Unions, which have fiercely opposed the measures, still hoped Saturday to force Macron to back down, though the day's protests against the reform were far smaller than some previous ones.

"This is the final stretch," Marylise Leon, deputy leader of the CFDT union, told the broadcaster Franceinfo on Saturday. "The endgame is now."

Tensions flared in the evening, with Paris police saying they had made 32 arrests after some protesters threw objects at security forces, with rubbish bins burned and windows broken.

This week, Macron twice turned down urgent calls by unions to meet with him in a last-ditch attempt to get him to change his mind.

The snub made unions "very angry", said Philippe Martinez, boss of the hard-left CGT union.

"When there are millions of people in the streets, when there are strikes and all we get from the other side is silence, people wonder: What more do we need to do to be heard?" he said, calling for a referendum on the pensions reform.

The interior ministry said some 368,000 people showed up nationwide for protests -- less than half of the 800,000 to one million that police had predicted.

In Paris, 48,000 people participated in rallies, compared to police forecasts of around 100,000.

Unions, who put the attendance figure at a million, had hoped turnout would be higher on a Saturday when most people did not have to take time off work to attend. On February 11, also a Saturday, 963,000 people demonstrated, according to police.

On Tuesday's last big strike and protest day, turnout was just under 1.3 million people according to police, and more than three million according to unions.