The country's busiest airport Charles de Gaulle is the worst hit, with 1-in-5 flights on Saturday expected to be cancelled.
Dozens of flights will be cancelled on Saturday at France's busiest airport, amid an ongoing dispute over wages and working conditions.
With firefighters on strike, the French civil aviation authority has requested preventive flight cancellations and closed part of the runways for safety reasons which will impact 1-in-5 flights at Roissy-Charles-de-Gaulle Airport between 7am and 2pm.
On Friday about a hundred out of 1,300 flights were cancelled at the airport, while the other major airport in the Paris region, Orly, was not affected.
"The movement continues among firefighters, who are dissatisfied with management's proposals on their pay scale" union chief Daniel Bertone said.
Firefighters were joined by employees and subcontractors from the Paris airports' management company ADP, as part of an inter-union and inter-profession action for wages and working conditions.
Negotiations on Friday fell through, and there's a risk of strikes next weekend as well, the start of the summer school holidays when there's traditionally a peak in airport traffic.
Air France has already announced it will cancel around 10% of its short and medium-haul flights on Saturday. Long-haul flights will not be affected.
What are the striking workers asking for?
The workers are asking for a 6% pay raise dating back to 1 January to compensate for inflation. Management has proposed a 4% raise from 1 July.
Unions say this offer doesn't make up for the 5% reduction in salaries already accepted by employees as part of the cost-cutting plan imposed by the company during the COVID pandemic in 2020-2021.
A spokesperson for the ADP management company said that negotiations have not been successful, but social dialogue remained open.
Because of the industrial action and flight cancellations, the airport is advising passengers to show up three hours before an international flight, and two hours before a domestic or European flight.
A French government spokesperson said on Friday that they will "continue to discuss with the unions to find a way out of the crisis."
"The idea that our compatriots cannot go on holiday is not viable," said Olivia Gregoire.