An official says one of four people arrested this week amid fears they were planning an attack in France had been under house arrest and was convicted two years ago of planning to join extremists in Syria.

A judicial official confirmed on Friday that Youssef Ettaoujar, convicted in 2014 along with two others, is among the group being questioned following Wednesday's arrests.

Ettaoujar, 28, finished serving his prison sentence in October and was under house arrest as part of France's state of emergency, in place since the Nov. 13 Paris attacks that killed 130, the judicial official said, on condition of anonymity due to the ongoing investigation.

His companion is also among the four arrested. It wasn't clear whether she is the mother of his daughter, who is named Jihad.