"Last night we struck the region of Tikrit as part of the coalition" aiding the Iraqi army battle IS fighters, a spokesman for France's armed forces said, noting it was the first time a French strike had targeted that area of northern Iraq.
The official did not specify whether jets or drones staged the strikes, and declined to detail targets of the attack.
US forces earlier announced they had led an air strike against IS units in Tikrit with coalition allies at the request of Iraqi Prime Minister Haider al-Abadi.
Thousands of Iraqi soldiers, police officers and paramilitary forces have been deployed to retake Tikrit, which is being ferociously defended by a large number of IS fighters who have booby-trapped streets and buildings in the city with bombs.