Much of France ground to a halt on Thursday as transport workers went on strike - joined by teachers, doctors, police, firemen and civil servants - while smoke and tear gas swirled through the streets of Paris as some protests turned violent, leading to dozens of arrests.

On Friday there were heavy cancellations of rush-hour trains into Paris and 10 out of 16 metro lines were closed while others ran limited services. Traffic jams totalling more than 350 kilometres clogged the main roads in and around the capital, according to traffic app Styadin, as many commuters took to their cars.

Rail workers extended their strike through Friday, while unions at the Paris bus and metro operator RATP said their walkout would continue until Monday.

"We're going to protest for a week at least, and at the end of that week it's the government that's going to back down," said 50-year-old Paris transport employee Patrick Dos Santos.

The strike pits Macron, a 41-year-old former investment banker who took office in 2017 on a promise to open up France's highly regulated economy, against powerful unions who say he is set on dismantling worker protections.

On Thursday the industrial action brought tens of thousands of protesters into the streets in Paris and forced the closure of the Eiffel Tower and parts of the Louvre Museum.

Union leaders were buoyed by the number of healthcare staff, railway workers and teachers who heeded the strike call, and by the numbers who showed up at an anti-government march in Paris and other French cities.

Macron wants to simplify France's unwieldy pension system, which comprises more than 40 different plans. Rail workers and mariners can for instance retire up to a decade earlier than the average worker.

Macron says the system is unfair and too costly and that the French will have to work longer, though he appears reluctant to simply raise the retirement age of 62.

Australian Associated Press