A strike by French air traffic controllers is disrupting travel. About 40% of flights at Paris airports are canceled, along with half of flights in Nice and 30% of flights in Marseille, Lyon and some other cities.

The French civil aviation agency said on Tuesday it had asked airlines to reduce flights at Paris' airports by 25% on July 3 following notification of a strike by air traffic controllers.

Flights crossing France’s airspace, even those not destined for the country, faced delays and rerouting at the start of the summer vacation period.