Paris air traffic controllers began a five-day strike on Monday, causing flight delays and cancellations.
About half of flights at Orly airport were canceled, France's civil aviation authority said, adding that only domestic flights were called off entirely. International flights and trips to France's overseas territories went ahead, albeit with delays of about one hour.
Travelers at Charles de Gaulle, the larger of the two Paris airports, faced delays but no cancellations.
The civil aviation authority asked travelers to contact their airlines directly for flight information.
The CGT union, which plans to continue the strike through Friday, is protesting a reorganization plan that would bring all of Paris' air traffic controllers to work at a single site.