Policemen also found the body of a dead woman in the house and a surviving 3-year-old boy, the spokesman for the Interior Ministry, Pierre-Henry Brandet, said on BFM TV minutes after the elite RAID unit stormed the house.
The woman was "most probably the wife" of the commander, prosecutor Vincent Lesclous told reporters.
"We have no certainty about the motivations" of the assailant, Lesclous added.