The plan was in an “advanced stage” and the person arrested was implicated at a “high level,” Cazeneuve said Thursday. He accused the individual of belonging to a terror network that planned to strike within France.

The arrest was the result of a detailed investigation that took place over several weeks, he said during a televised address.

Following what Cazeneuve characterized as the “important arrest,” French police carried out an anti-terror operation in Argenteuil, outside Paris. Residents of a building were evacuated.