PARIS — Schools were shuttered, the Eiffel Tower stood closed and commuters faced widespread disruption across France on Thursday, as public and private sector workers took part in a mass strike in protest against the government’s plan to overhaul the pension system.

France is no stranger to industrial action but the nation-wide walk out — dubbed “black Thursday” by French media — amounts to one of the greatest challenges yet to President Emmanuel Macron’s sweeping societal reforms that many see as threatening the French way of life.

French railway stations were empty Thursday, with around nine out of 10 of high-speed trains cancelled. Signs at Paris’ Charles de Gaulle Airport showed “cancelled” notices, as Air France called off about 30 percent of domestic flights.

In Paris, many subway stations were closed Thursday, prompting commuters to take to shared bikes and electric scooters, while others worked from home or looked after their children who were unable to attend school. Some 51 percent of primary school teachers and 42 percent of secondary school teachers went on strike across France on Thursday, according to the education ministry.

Videos of half-empty subways and commuter trains, as well as people beginning to take to the streets in major French cities including Marseille, Lyons and Nantes circulated on social media. In the capital, some 6,000 police were deployed for what is expected to be a major demonstration.

Bracing for potential violence and damage, the city’s police chief instructed all businesses, restaurants and cafes to close along the major march routes. Authorities also issued a ban on protests on the Champs-Elysees avenue, around the presidential palace, parliament and Notre Dame Cathedral.

Yellow vest activists plan to join unions at the protests in Paris and cities around the country to continue to amplify their call for greater economic justice. France’s Interior Minister Christophe Castaner warned Wednesday that vandals or so-called “casseurs” could infiltrate the protests and cause damage as they did in numerous yellow vest protests last year.

Philippe Martinez, secretary general of one of France’s most powerful union confederations, told French television network BFMTV that there were “never vandals or extremists” in the confrontations processions but that the unions were not responsible for what happened outside those processions.

Macron wants to simplify complex French pension regimes into one single points based system so that all French workers have the same pension rights.

He says it will make the system fairer and is what’s needed to transform France so it can compete globally in the 21st century.

But unions argue it will require people to work longer, will reduce pensions and will help undermine France’s social safety net.

There are currently dozens of different pensions systems where some professions have special privileges — air crews and rail workers for example are allowed early retirement while other professions, such as lawyers and doctors, pay less tax. The government has promised the legal retirement age of 62 won’t change and that some people with physically demanding jobs would be able to retire earlier, according to the Associated Press.

It was unclear Thursday how long the strike would last.

Unions have said it is an indefinite movement and hope to keep up the momentum in order to force the government to make concessions.

“It will be this war of attrition over the coming days and weeks to see whether or not the strikers or the unions will decide to go back to work before he needs to back down,” said Joseph Downing, who focuses on French politics at the London School of Economics, referring to Macron.

Downing said the strike was different from the yellow vest demonstrations because it was a single issue protest and people knew what they are fighting for meaning there was potential for it to last for a long time.

However, he cautioned that Macron has won wars of attrition before.

“He’s weathered a few storms, it may be his biggest test but it’s not his first,” he added.

Saphora Smith reported from London. Nancy Ing from Paris.