France is braced for nationwide strikes that are expected to cause widespread disruption to the travel network.
Flights and ferries are being targeted, with industrial action by transport workers, as well as teachers and hospital staff.
It's part of a row over plans to force citizens to retire later or face reduced pensions.
Aer Lingus and Ryanair have both tweeted to say that their services will be affected by the industrial action.
Due to a national strike in France, EI524 (Dublin to Paris) and EI525 (Paris to Dublin) on Thursday 05 December are cancelled. Guests whose flights are cancelled have been notified and can choose to rebook or opt for a refund.
— Aer Lingus (@AerLingus) December 4, 2019
Most of France's high-speed trains will not run while large parts of the Paris Metro are closed.
French politics expert Nabila Ramdani says it's the largest walkout in decades:
"In fact it's likely to be the worst day of action since the national strike that we seen back in 1995, one that will not only paralyse all transport systems including international travel but will also threaten vital services."