Gunmen and bombers attacked restaurants, a concert hall and a sports stadium at locations across Paris on Friday, killing at least 153 people in a deadly rampage, some 200 people were injured, that a shaken President Francois Hollande called an unprecedented terrorist attack.
The coordinated assault came as France, a founder member of the US-led coalition waging air strikes against Islamic State fighters in Syria and Iraq, was on high alert for terrorist attacks ahead of a global climate conference due to open later this month.
"The terrorists, the murderers raked several cafe terraces with machine-gun fire before entering (the concert hall). There were many victims in terrible, atrocious conditions in several places," police prefect Michel Cadot told reporters.
After being whisked from the soccer stadium near the blasts, Hollande declared a nationwide state of emergency – the first since the end of World War Two – and announced the closure of France's borders to stop perpetrators escaping.
The Paris metro railway was closed and schools, universities and municipal buildings were ordered to stay shut on Saturday. However some rail and air services are expected to run.
"This is a horror," the visibly shaken president said in a midnight television address to the nation before chairing an emergency cabinet meeting.
He later went to the scene of the bloodiest attack, the Bataclan music hall, and vowed that the government would wage a "merciless" fight against terrorism.
All emergency services were mobilized, police leave was canceled, 1,500 army reinforcements were drafted into the Paris region and hospitals recalled staff to cope with the casualties.
The prosecutor's spokeswoman said she could not say whether any gunmen were still at large.
Radio stations broadcast warnings to Parisians to stay home and leave the streets and urged residents to give shelter to anyone caught out in the street.
The deadliest attack was on the Bataclan, a popular concert venue where the Californian rock group Eagles of Death Metal was performing. The concert hall is just a few hundred meters from the former offices of the satirical weekly Charlie Hebdo, target of a deadly attack by Islamist gunmen in January.
Some witnesses in the hall said they heard the gunmen shout Islamic chants and slogans condemning France's role in Syria.
"We know where these attacks come from," Hollande said, without naming any individual group. "There are indeed good reasons to be afraid."
France has been on high alert ever since the attacks on the Charlie Hebdo newspaper and a kosher supermarket in Paris in January killed 18 people.
Those attacks briefly united France in defense of freedom of speech, with a mass demonstration of more than a million people. But that unity has since broken down, with far-right populist Marine Le Pen gaining on both mainstream parties by blaming immigration and Islam for France's security problems.
It was not clear what political impact the latest attacks would have less than a month before regional elections in which Le Pen's National Front is set to make further advances.