Transport networks have ground to a near halt as part of a walkout to force President Emmanuel Macron to abandon his pension reform plans.
The protest threatens to paralyse France for days with public transport in Paris and cities across the country on shutdown.
Planes have been grounded, trains axed and Eurostar services cancelled leading to school closures, flights cancelled and tourists urged to stay away from tourist spots.
Here's all you need to know about the French transport strikes.
When are the strikes taking place?
The nationwide strikes began at 7pm on Wednesday, December 4 and are expected to last over the weekend.
Workers at the national railway SNCF stopped on work on Wednesday evening while other services shut down on Thursday morning indefinitely.
But it is unclear exactly how long they will last. Unions say it is an indefinite movement and hope to keep up momentum at least for a week, in hopes of forcing the government to make concessions. Transport Minister Elisabeth Borne said she expects the travel troubles to be just as bad Friday.
Some union bosses have threatened to continue the industrial action until Mr Macron backs down on his pension overhaul plans.
Why are workers striking?
Workers are angry over Mr Macron's plans to overhaul the country's pension system.
Currently, 42 different schemes are in place across the country and the president wants to streamline the process.
Mr Macron believes the retirement reform is central to his plan to transform France so it can compete globally in the 21st century. The government argues France's 42 retirement systems need streamlining.
While Macron respects the right to strike, he "is convinced that the reform is needed, he is committed, that's the project he presented the French in 2017" during his election campaign, the presidential official said. The official was not authorized to be publicly named.
But workers fear the plans mean they will have to work longer and shrink their pensions. And they see this fight as crucial to saving France's social safety net. Some private sector workers welcome the reform, but others support the strike.
The high commissioner for pensions is expected to detail reform proposals next week, and the prime minister will release the government's plan days after that.
Who is going on strike?
Workers from all sectors are taking part in the strike including hospital staff, Air Traffic Controllers, transport workers on SNCF, Eurostar and Metro, police, lawyers, Airport Fire Services and teachers.
The French government said 55% of teachers would be on strike on Thursday and hospitals will also be affected.
Paris police chief Didier Lallement said 6,000 police officers would be deployed around Paris as activists - many in yellow vests representing France's year-old movement for economic justice - gathered for a major march through the capital.
How have the strikes affected France?
The walkout is expected to hit transport the hardest with flights, trains and buses suffering cancellation. Most of the Paris subway system has also come to a halt and stations closed.
No tickets are available on Eurostar trains until Tuesday, with the company saying it had cancelled almost 100 services between now and then.
Air France has had to cancel around 30% of its domestic flights while easyJet, British Airway and Ryanair have grounded many of their flights in and out of France.
Thousands of holidaymakers are likely to be affected by flight cancellations and delays, and the Foreign Office has warned of severe delays on public transport.
Tourists are being warned to stay away from famous monuments such as the Eiffel Tower, while others such as The Louvre may close rooms and open later as a result of the strikes.
Hotels across Paris reported receiving numerous cancellations ahead of the strike, as wary tourists eyed closing transport routes and decided to skip their Paris trips.
SNCF expects nine out of 10 high-speed trains to be cancelled.
Thousands of extra police officers have been deployed across the capital with unions planning large-scale protests. Authorities are warning of possible violence and damage and ordered all businesses, cafes and restaurants along the route to close.