Police fired tear gas to repel violent black-clad anarchists in Paris on Thursday as hundreds of thousands of mainly peaceful protesters marched across France against President Emmanuel Macron's plan to raise the pension age.

In a ninth day of nationwide protests, train and air travel was disrupted while teachers were among many professions to walk off the job, just days after the government pushed through legislation to raise the retirement age by two years to 64.

In central Paris, where demonstrators were generally peaceful, smaller groups of "Black Bloc" anarchists smashed shop windows, demolished street furniture and ransacked a McDonalds restaurant. Clashes ensued as riot police moved in and drove back the anarchists with tear gas and stun grenades.

BFM TV quoted police as saying 26 people were arrested.

Labour unions fear that protests could turn more violent if the government does not take the growing popular anger over the pension curbs into consideration.

Roissy-Charles De Gaulle airport outside Paris was hit by a wildcat walkout by workers.

Police fired tear gas at some protesters in several other cities, including Nantes and Bordeaux in the west, and used water cannon against other in Rennes in the northwest.

In the western town of Lorient, Ouest-France newspaper said projectiles caused a brief fire in the yard of a police station.

"There is a lot of anger, an explosive situation," the leader of the hardline CGT union, Philippe Martinez, said at the start of a rally in Paris. Union leaders called for calm but were angry with what they called Macron's "provocative" comments.

Macron broke weeks of silence on Wednesday on the new policy to say he would stand firm and the law would come into force by the end of the year. He compared protests to the Jan. 6, 2021, storming of the U.S. Capitol.

Opinion polls have long shown that a majority of voters oppose the legislation. They were further angered by the government's decision last week to ram the pension changes through parliament without a vote.

Many slogans and banners took aim at the president, who avoided reporters as he arrived in Brussels for a European Union leaders summit.

The French Interior Ministry said 1.09 million protested across the country, including 119,000 in the capital which was a record since the protests started in January. The CGT union said 3.5 million people marched in the country, equalling a previous high on March 7.

"I came here because I oppose this reform and I really oppose the fact that democracy no longer means anything," Sophie Mendy, an administrative medical worker, told Reuters at the Paris rally. "We’re not being represented, and so we’re fed up."

'THE STREET HAS LEGITIMACY'
Electricity output was cut on Thursday as unions raised pressure on the government to withdraw the law. Flight services will continue to be reduced at the weekend, the civil aviation authority said.

Protests also targeted oil depots and blocked a liquefied natural gas terminal in the northern city of Dunkirk. Rolling strikes at oil depots and refineries have led to major petrol shortages in the southeast and west of France.

Protests against the new law, which also accelerates a planned increase in the number of years one must work to draw a full pension, have drawn huge crowds in rallies organised by unions since January.

Most have been peaceful but anger has mounted since the government bypassed a vote in the lower house of parliament, where it lacks an absolute majority and was not sure of getting enough support.

The past seven nights have seen demonstrations in Paris and other cities with rubbish bins set ablaze and clashes with police.

The latest wave of protests represents the most serious challenge to Macron's authority since the "Yellow Vest" revolt of disgruntled lower-income people four years ago.

"The street has a legitimacy in France. If Mr Macron can't remember this historic reality, I don't know what he is doing here," 42-year-old entertainment show worker Willy Mancel said at the Nantes rally.

Losing pay days when on strike takes a toll at a time of high inflation, and the government will be hoping that protests and strikes eventually lose steam.