Authorities foiled an ISIS-linked attack in Paris on Saturday, arresting a 15-year-old boy suspected of preparing an imminent “violent action,” two judicial sources told Reuters.

The boy, who was not identified, had been under house arrest since the coordinated Nov. 13 Paris attacks that killed 130 people. After that deadly episode, France declared a state of emergency. It was not immediately clear why the teen was under house arrest.

The boy was allegedly planning an attack on a public place, a source told Reuters. Another source said that the teen was in contact with a known Islamic extremist, Rashid Kassim.

Kassim, a Syrian-based jihadist, is suspected of being behind a plot to attack a Paris train station this week. Authorities thwarted that scheme, however, arresting seven people, including four women.

The train station plan was uncovered after an abandoned car filled with gas cylinders was found outside of Notre Dame Cathedral last Sunday.