 "At least 140 dead in Paris attacks, worst since WWII")
President Francois Hollande condemned it as terrorism and pledged that France would stand firm against its foes.
The worst carnage was at a concert hall hosting an American rock band, where scores of people were held hostage and attackers ended the standoff by detonating explosive belts.
Police who stormed the building, killing at least three attackers, encountered a bloody scene of horror inside.
Paris Prosecutor Francois Molins said as many as five attackers were killed, though it was not clear how many there were altogether and how many, if any, were still at large.
Authorities said the death toll could exceed 140 for at least six sites, including the national stadium and a tight circle of popular nightspots.
Hollande declared a state of emergency and announced that he was closing the country's borders. Metro lines shut down and streets emptied on the mild fall evening as fear spread through the city, still aching from the horrors of the Charlie Hebdo attack just 10 months ago.
The attack unfolded with two suicide bombings and an explosion outside the national stadium during a soccer match between the French and German national teams. Within minutes, according to Paris police chief Michel Cadot, another group of attackers sprayed cafes outside the concert hall with machine gunfire, then stormed inside and opened fire on the panicked audience. As police closed in, they detonated explosive belts, killing themselves.
Hollande, who had to be evacuated from the stadium when the bombs went off outside, later vowed that the nation would stand firm and united:,"A determined France, a united France, a France that joins together and a France that will not allow itself to be staggered even if today, there is infinite emotion faced with this disaster, this tragedy, which is an abomination, because it is barbarism."
There was no immediate claim of responsibility for the attacks, although jihadists on Twitter immediately praised them and criticized France's military operations against Islamic State extremists.
In addition to the deaths at the concert hall, dozens were killed in an attack on a restaurant in the 10th arrondissement and several other establishments crowded on a Friday night, police said.