Environmental protesters broke into the runway of Paris-Orly airport, disrupting the airport that reopened after three months.

Dozens of activists from the "Anti-extinction" group broke into the runway of Paris-Orly Airport, lighting flares and locking themselves into bicycles to protest the airport reopening on June 26.

Before the arrest, activists held up the banners "Save lives, not planes" and "15 billion to restart the disaster", referring to the French government spending 15 billion euros (about 15 billion euros).

The group "Rebellion against extinction" then posted on Twitter said 29 people had been arrested, including a journalist from eco-news site Reporterre.

Franck, an activist with the group "Rebellion against extinction", said the group warned the airport security forces 20 minutes before rushing to the runway, adding that he was surprised that French police had to join.

"They talk a lot about airport security, but anyone can come in," Franck said.

The demonstration caused one flight to be delayed for several hours and the rest to divert to other runways.

The French finance minister has called for the reduction of domestic air routes to encourage people to travel by train and other means.

The group "Rebellion against extinction" made a similar move at London Heathrow Airport last October.