Emilie Koenig, a UN and US blacklisted Frenchwoman suspected of recruiting fighters for ISIL, has been arrested by Kurdish forces in Syria, her mother said on Tuesday.
The 33-year-old daughter of a gendarme is "being held in a Kurdish camp and has been interrogated and tortured", her mother told Ouest-France newspaper.
Koenig went to Syria in 2014 and three of her children were born there.
She was put on the United Nations list of the most dangerous fighters and a year later appeared on a terrorist list issued by the US.
Koenig converted to Islam after marrying her first husband, a man of Algerian origin, who was arrested for drug trafficking.
She learnt Arabic, changed her name to Samra and started wearing a veil. She left for Syria to join her new partner, who was later killed.
She appeared in several propaganda videos in which she appealed for jihad "as long as the enemy is around".
Koenig's mother said she wanted to return to France and to seek forgiveness of her family, her friends and her country.