Adm Arnaud Coustilliere told reporters that many of the cyber attacks were carried out by “more or less structured” groups, including some well-known Islamist hacker groups.
The attacks appeared to involve primarily relatively minor denial-of-service attacks. He said they have hit sites representing sectors from military regiments to pizza shops.
Meanwhile, French president Francois Hollande has insisted that any anti-Muslim or anti-Semitic acts must be “severely punished” as he sought to calm rising religious tensions.
With 120,000 security forces deployed to prevent future attacks, nerves jumped on Wednesday night when a car rammed into a policewoman guarding the president’s palace. The incident at the Éysée Palace had no apparent links to last week’s shootings and might have been an accident, prosecutors and police said.
The country is tense since 20 people, including three gunmen, were killed in last week’s rampage. It began at the offices of satirical newspaper Charlie Hebdo, which buried several staff members yesterday. Charlie Hebdo had been repeatedly threatened over its caricatures of the Muslim prophet Mohammed.
Two of the attackers claimed allegiances to al-Qaida in Yemen and another – who targeted a kosher supermarket – to the "Islamic State" group.