Some 700 French adults, one-third of them women, and about 500 children are in terrorist-held areas in Iraq and Syria, an official at the French president's office said on Friday, raising potential legal challenges over how to handle them.
The presidency official said that half of the 500 children were born there, and in total about 2,000 French nationals or residents had gone to the two countries to join terror groups, of whom between 200 and 300 had been killed.
France, like other European nations, is wrestling with how to deal with returning terrorists.
Interior Minister Gerard Collomb, said in August that 271 terrorists had returned to France and were under investigation.
Around 1,400 foreign wives and children of suspected Daesh terrorists are being held by Iraqi authorities in a camp after government forces expelled the terrorist group from one of its last remaining strongholds in Iraq.