A high court has ordered the French state to pay damages to the parents of a teenage girl who managed to go to Syria in an apparent attempt to join Islamic extremists even though they had reported her missing to the police.

The council of state ruled Wednesday that border police at a Paris airport should have checked the register of wanted people before letting the 17-year-old fly to Turkey on her way to Syria in 2013.

The court found the French state responsible for the police services' "negligence" and awarded 15,000 euros in "moral damages" plus costs to the parents. No details were given about where the girl is now.

More than a third of the nearly 700 French citizens who have reached Iraq and Syria are women, an increasing number of them teenagers, officials have said.