Strike action by French public sector workers has been causing major disruption to air and rail services across the country.
Commuter transport was badly affected in Paris
Hundreds of domestic and European flights have been cancelled, and public transport in major cities has been seriously hit.
Thousands of people took to the streets in Paris and other French cities in support of the strike, called to protest against pension reforms.
Public sector employees risk losing privileges - such as a shorter contribution period before they are entitled to draw a full pension - if the reforms go ahead.
I've had enough - the unions really know how to take us hostage
All but one of the country's main unions are taking part in the stoppage, which officially began at 2000 local time (1800 GMT) on Wednesday. It is due to end at 0200 on Friday.
The Education Ministry reported that 33% of secondary school teachers and 46% of primary school teachers had joined the strike.
80% of flights across France cancelled
70% of flights from Paris Charles de Gaulle and Orly airports cancelled
One service in three running on Paris metro, and three lines closed
One Paris suburban train in every two running
60% of Paris buses running
At least 30,000 march in southern city of Marseille
The work of the postal and customs services was also affected.
At least 30,000 people marched through the southern port city of Marseilles in a show of support for the strikers, while thousands of protesters braved a cold drizzle to demonstrate in Paris.
"The government's tactics border on fascism," town hall worker Marc Estrada told Reuters news agency. "The public response speaks for itself."
Some 80% of all flights across France were to be cancelled, the French civil aviation office said.
National carrier Air France said it was cancelling 55% of its short- and medium-haul flights. All long-haul services will continue to operate.
Many airlines are offering refunds to affected passengers.
There are reportedly widespread cancellations on the high-speed TGV system.
Train services and the Paris metro have also been badly hit, leading to massive traffic jams as commuters turned to road transport.
Pavements were crowded with people walking to work, and there were sitings of businessmen in suits roller-blading to work.
"I've had enough," 44-year-old Josette Chapon told the Associated Press news agency as she waited for a taxi. "The unions really know how to take us hostage."
But Bernard Thibault, head of the Communist-affiliated CGT union, said there could be more strikes.
"We have to resort to this type of protest when, despite our efforts, the government isn't listening to us," he told the Associated Press news agency.
In November last year at least 30,000 public sector workers, including railway workers and air traffic controllers marched through Paris after unions were angered at government moves towards privatisation, pension reforms and spending cuts.
It was the biggest labour challenge to France's centre-right government since its election in June 2002.