France is to press terrorism charges against seven suspected Islamic militants over a series of attacks on Jewish targets.
They were among a dozen people arrested on Saturday following raids across the country. Five will face no further action.
After Wednesday's discovery in Paris of a large cache of weapons and bomb making equipment, state prosecutor described the group as the most sophisticated domestic terror network France has faced in more than a decade.
"In terms of dangerousness and preparations, we've not seen any like this since 1996," said Paris prosecutor Francois Molins.
The arrests raids were sparked by a grenade attack on a kosher grocery store outside Paris last month.
The incident further unsettled Europe's largest Jewish community, which was shaken when an al Qaeda-inspired gunman shot dead three Jewish children and a rabbi in Toulouse in March.
Investigators also believe some of the group were planning to go to Syria to fight against President Bashar al-Assad's regime.
