An empty platform is pictured during a railway strike at the Lyon Perrache train station, France, on Thursday. AP

A nationwide strike shut down public transport, schools and other services across France on Thursday as unions kicked off an open-ended strike against President Emmanuel Macron's plans for a "universal" pension system they say will force millions of people to work longer.

Parents scrambled to organise daycare as teachers walked off the job or were unable to get to work, and many employees were working from home or forced to take the day off as trains, metros and buses were cancelled.

People look at the information board reading the different planes cancelled during a strike at the Paris Orly airport in Orly. AFP

Union leaders have vowed to keep up their protest unless Macron drops the pension overhaul, the latest move in the centrist president's push to reform wide swathes of the French economy.

"The idea of social concertation that Macron says is so important in fact doesn't exist," the head of the CGT union, Philippe Martinez, said on BFM television Thursday.

Around 90 percent of high-speed TGV trains as well as regional lines were cancelled, and Air France has axed 30 percent of domestic flights and 15 percent of short-haul international routes.

In Paris, 11 of the 16 metro lines were shut down and others had just bare-bones service during the morning rush hour, and the Eiffel Tower turned away tourists because of the strike.

Transilien regional trains are seen at the Saint-Lazare railway station in Paris during a strike. Christian Hartmann/Reuters

"There are not enough employees to open the monument in secure conditions," the tower's operator said in a statement.

The strike -- which is open-ended and could last several days -- has drawn comparisons with the showdown between government and unions over pensions in November-December 1995, when the country was paralysed for around three weeks.

Unions won that battle, and are banking on widespread support from both public and private-sector workers against Macron's reform.

The government has yet to unveil the details of the project, but officials have conceded that people will have to work longer for the system to remain financial viable.

Outcome uncertain

The strikes will be a major test of whether Macron, a former investment banker who came to power on the back of a promise to transform France, has the political strength to push through one of his key campaign pledges.

Railway workers are pictured the morning of a mass strike at the Gare St-Charles station in Marseille, France. Daniel Cole/AP

He has already succeeded in controversial labour and tax reforms aimed at encouraging hiring, as well as an overhaul of the state rail operator SNCF, long seen as an untouchable union bastion.

He has also largely seen off the "yellow vest" protests against declining living standards that erupted a year ago, but that anger could feed into the latest protest.

"The moment of truth for Macron," the Le Monde daily wrote in Thursday's edition. "The next days are a decisive test for the head of state."

The SNCF said international lines including the Eurostar and Thalys services were severely disrupted, and Education Minister Jean-Michel Blanquer said Wednesday that he expected just three in 10 schools would be able to open.

'Special regimes'

The strike is the latest in a series of protests against Macron this year by the "yellow vests" as well as police, firefighters, teachers, hospital workers and lawyers.

Passengers check the information board at the Orly airport, south of Paris, on Thursday. Francois Mori/AP

Macron wants to implement a "universal" retirement system that would do away with 42 "special regimes" for sectors ranging from rail and energy workers to lawyers and Paris Opera employees, which often grant workers higher pensions or early retirement.

But unions say the changes would effectively require millions of private-sector workers to work beyond the legal retirement age of 62 if they want to receive the full pension they have been promised.

Prime Minister Edouard Philippe, who has acknowledged French workers will gradually have to work longer, is set to unveil details of the reform on December 12.

Interior Minister Christophe Castaner said Wednesday that some 250 demonstrations are expected nationwide, warning that a radical fringe of protesters could cause trouble.

A man rides a bicycle in a street of Lille during a strike by French transportation workers on Thursday. Reuters

Paris police chief Didier Lallement said around 6,000 members of the security forces would be deployed in the capital alone, with 180 motorbikes used to respond fast to any rioting.

Two major demonstrations are planned for Paris that will converge on the Place de la Nation, with officials ordering Paris businesses along the routes to close on Thursday.

British low-cost carrier EasyJet has cancelled 223 domestic and short-haul international flights and warned others risk being delayed.

Agence France-Presse