The operation took place in the small town of Lunel east of Montpellier in southern France, from where around 20 young people have left for Syria. Six of them, aged 18 to 30, have been killed since October.
Crack French security forces launched the operation at 6am in a building in the centre of the town, according to witnesses that spoke to AFP.
“Several unmarked cars drew up. Masked men got out and smashed in the doors to the apartments in the building,” said one resident of the block, who said they had threatened him.