Around 450 French nationals linked to the "Islamic State of Iraq and Syria" (ISIS) are being held by Kurds or detained in refugee camps in north-eastern Syria, AFP reported Tuesday.
"In the north-eastern zone of Syria, we think that there are between 400 and 450 French people, some in camps, others held as prisoners, including children," French foreign minister Jean-Yves Le Drian told parliament's foreign affairs committee.
He said only the children could be repatriated if they were orphans or if their mothers gave permission.
France has long insisted that its adult citizens captured in Iraq or Syria must face trial locally, refusing to repatriate them despite the risk they could receive death sentences.
"Our position is still the same and we will not shift: fighters must be judged where they have committed crimes," Le Drian said.
More than 100 French fighters are still present in Idlib, he said.