The police operation was still ongoing Tuesday morning and was taking place in the small town of Lunel, east of Montpellier.
Security forces launched the operation at 6:00 am local time in a building in the town centre.
"Several unmarked cars drew up", said a resident of the building.
"Masked men got out and smashed in the doors to the apartments (...) in the end they arrested my neighbour above me", he added.
Another witness said the police took away his brother.
Lunel is a small town of 26,000 people from where around 20 young people have reportedly left for Syria.
Six of them, aged 18 to 30, have been killed since October.