The gunmen who attacked the concert hall in Paris Friday night (November 13) ordered the audience to lie down while they continued to shoot, a witness said in the early hours of Saturday morning (November 14).

In what French President Francois Hollande called an unprecedented terrorist attack, at least 120 people were killed on Friday night across the capital in attacks at restaurants, a concert hall and a sports stadium.

A Paris city hall official said gunmen systematically slaughtered nearly 100 people attending the rock concert by the Eagles Of Death Metal at the Bataclan music hall. Anti-terrorist commandos eventually launched an assault on the building, killed the gunmen and rescued dozens of shocked survivors.

Jerome Bartelemy, who was in the sold-out concert venue, said the two gunmen he saw were no older than 25.

"They told us to lie down, there was one who kept gesturing for us to get down. We all lay down, the whole room lay down. I was completely under other people, and they (the attackers) kept shooting," Bartelemy said.

He added he was surprised at how calm one of the shooters was.

"The one I saw, he was wearing a black tracksuit with white stripes, he was no older than 25. The guy had brown hair, he was pretty calm. That's what really surprised me. At a certain point, I turned around and we were wondering if they were real bullets or not, and I saw him shoot someone and then I understood," he said.

Some 40 other people were killed in up to five other attacks in the Paris region, the city hall official said, including an apparent double suicide bombing outside the national stadium where Hollande and the German foreign minister were watching a friendly soccer international.

Paris Public Prosecutor Francois Molins said the overall death toll was at least 120. Five assailants had been "neutralised".