Francois Molins told the daily Le Monde that “hundreds” of women would return from Syria in the next few months.
French authorities had probably been wrong “at first to say that they were just following their husbands and that they were restricting themselves to domestic chores in Syria”, he said.
“Now they are systematically arrested when they return and taken intocustody.”
He said 59 women have been charged in France of whom 18 were serving prison sentences.
The prosecutor also noted a rise in the number of radicalised girls in France “with very worrying profiles”.
“They are sometimes behind terrorist plots which, on an intellectual level,are quite far along,” he told the paper.
Twenty-three boys and 12 girls under the age of 18 are currently facing charges in France for terror-related offences.
Molins said he was worried about the potential radicalisation of youngteens who had been taken by their parents to Syria or Iraq and might have appeared in IS execution videos or undergone military training.
“They are going to be real time bombs,” Molins said.
He estimated that around 20 minors were currently fighting alongside Isis militants in Syria or Iraq.
Around 700 French citizens are currently in conflict zones in Syria and Iraq, Molins said.
Isis claimed responsibility for the November 2015 attacks on Paris that killed 130 people and the group said one of its followers drove the truck in the attack on the Nice waterfront in July in which 86 people died.