Flights to and from French airports, as well as those flying in French airspace, were cancelled on Tuesday as the USAC-CGT union went on strike in the latest protest over labour law reforms.
France's Civil Aviation Authority, DGAC, did not actually recommend any airlines to cancel flights, but warned passengers to expect delays.
In the end airlines took it upon themselves to cancel flights.
Ryanair has grounded 102 flights for the day - the full list of which can be seen here.
The airline wrote that further delays and cancellations "were likely", and urged its customers to sign a petition against what it said were "tiny groups of Air Traffic Control (ATC) unions going on strike and closing skies over Europe".
EasyJet made at least 46 cancellations, noting on its site that some 65 percent of its flights fly over French air space.
"This will have an impact on our flights to and from French airports, as well as those flying over French airspace," it said.
Aer Lingus flights also made cancellations, as did Spanish low-cost airline Vueling, though it remains unclear if those from Vueling are due to the labour law disputes.
Passengers will be informed of any cancellations, but are advised to check online before heading to the airport in all cases.
Air France has not made any changes to its schedule, but warned customers that "last-minute cancellations could not be ruled out".
Tuesday will see demonstrations across France against the new labour laws, as the government looks set to push the bill through parliament without a vote in the afternoon.