French police arrested two Egyptian-born brothers plotting an attack using either explosives or the lethal poison ricin, Interior Minister Gerard Collomb said.
He said French intelligence agents intercepted communications from the two men on the secure messaging platform Telegram.
“They are two young individuals of Egyptian origin who were preparing an attack,” Collomb told BFM TV. “They possessed instructions on how to build ricin-based poisons.”
A week ago, a Chechen-born Frenchman went on a stabbing rampage in central Paris, killing one person before police shot him dead, an attack that again exposed the difficulty European intelligence services face in keeping track of suspected extremists.
More than 240 people have been killed on French soil over the past three years in attacks launched by Islamist militants or individuals inspired by groups like Islamic State.
Collomb gave no further details on the arrest of the brothers.