Pictures of the scene in Paris showed people rushing to clear the area, and a heavy armed police presence. Two of the 10 known perpetrators were Belgian citizens and three others were French. Islamic State claimed responsibility.
The shooting took place around 9 pm, Paris time, near a branch of the Marks and Spencer chain. Eleanor, what more can you tell us about the incident?
A soldier stands guard near the Arc of Thriomphe at the top of the Champs Elysees avenue in Paris, after a fatal shooting in which a police officer was killed along with an attacker, Thursday, April 20, 2017.
Hollande held an emergency meeting with the prime minister Thursday night and planned to convene the defense council Friday morning. They were clearly targeting the police.
United States vice president Mike Pence said the shooting was the "latest reminder that terrorism can strike anywhere, any time" and his country "will not relent in our effort to end terrorism". Paris counterterrorism officials have also opened an investigation.
The UK strongly condemns the appalling terrorist attack in Paris.
A neighbour said: "I think everyone here is in shock".
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Authorities will remain on the highest alert, especially for possible threats to the election, he said.
Tourists were warned to go back to their hotels and to let family and friends know they were safe. "Traffic has stopped", she says. But the world's eyes are on France right now, and so anyone who wants to be noticed would do something in France right now.
He was among the officers who responded to the gun and bomb attack on the Bataclan concert hall in November 2015, part of a wave of assaults in Paris that killed 130 people. "And so anyone who wants to be noticed would do something in France".
Candidates cancelled or rescheduled final campaign events ahead of Sunday's first-round vote. Here in the US, the Obama administration aligned itself with those who wanted to murder policemen.
Jihadism and security have been major issues in the tightly fought presidential campaign.
Officers at the scene said they were searching for a potential second assailant, and Brandet said it could not be ruled out that there was another or others involved.
An attacker took a truck and drove down a crowded street in Nice during a Bastille Day celebration, killing 84.