Warplanes took off Monday from France's Charles de Gaulle aircraft carrier, newly deployed to the eastern Mediterranean, for operations over areas held by the Islamic State group in Iraq and Syria, military sources said.
Rafale jets loaded with bombs were catapulted from the carrier's flight deck Monday morning, an AFP reporter saw.
Speaking to AFP, the sources did not indicate the nature of the operations, which come 10 days after the deadly attacks in Paris that left 130 dead.
French President Francois Hollande said earlier in Paris: "We will intensify our strikes, choosing targets that will do the most damage possible to this army of terrorists."
The Charles De Gaulle has 26 fighters, more than doubling France's strike capacity in the US-led mission against IS.
France already has six Mirage and six Rafale jets stationed in the United Arab Emirates and Jordan.
A military source said their missions would overfly Turkey or Jordan to avoid Syrian anti-aircraft defences.
To avoid crossing paths with Russian planes, France is coordinating with Moscow via the US coalition headquarters in Qatar.
French and Russian naval commanders began exchanging information at the end of last week ahead of the deployment to the eastern Mediterranean, where Russia has several ships.
Russian President Vladimir Putin instructed his navy last week to work with the French "as allies".
After its operation in the Mediterranean, the Charles de Gaulle will head to the Gulf to relieve a US carrier.