A boulevard normally teeming with tourists, the Champs-Elysees has now become the site of an attack targeting police officers.
The shooting happened just a few hundred metres from the Arc de Triomphe.
Counterterrorism police have evacuated the area after a man using a semiautomatic weapon shot one police officer dead and injured two other people.
He tried to run from the scene but was shot dead himself.
A manhunt has been launched for a second attacker, believed to have entered the country from Belgium.
French Interior Ministry spokesman Pierre Henri Brandet says the officers were deliberately targeted.
“Just before 9pm in front of number 102, Avenue de Champs-Elysees, a vehicle stopped next to a police vehicle. A man jumped out of this vehicle and opened fire on the police vehicle, fatally wounding one officer. The man then tried to run onto the pavement, targeting the police officers there. He managed to wound two of them. They sustained serious injuries. The two police officers who were wounded and other nearby officers returned fire, and the attacker was killed.”
This witness, giving his name as Chelloug, says he feels lucky to have escaped with his life.
He was two metres from the targeted police van when he saw the gunman park his car nearby.
He says he heard six shots fired and saw a police officer hit the ground.
“He (the gunman) parked just behind the van, and he got out with a Kalashnikov, and I heard six gunshots. I thought they were firecrackers, because we all looked around the road and there was no-one. In fact, he was hidden behind the van and shooting at the police. I think he hit a policeman. As soon as the policeman opened the door of the van, he fell, I think. As soon as we saw that, we all ran back inside Alain Affelou. We hid, and I went up to the first floor, and we saw (the policemen) shoot him.”
Prosecutors are looking at terrorism as a possible motive in the attack.
The self-proclaimed Islamic State has claimed responsibility.
A statement released by the group’s media wing, Amaq, claims the attacker was a Belgian national named Abu Yousuf al-Belgiki.
Authorities have identified him as a 39 year-old from suburban Paris.
French president Francois Hollande says he is certain the attack was a terrorist act.
“The assailant was himself neutralised by other police officers. Our entire district has been cordoned off. Those present were evacuated. And we are convinced that the trails which can lead us in the inquiry will identify terrorists.”
Mr Hollande says a passer-by has been wounded in the shooting, but he provided no details.
Speaking before French officials, United States president Donald Trump has offered condolences and says people must remain strong.
“Well, first of all, our condolences from our country to the people of France. Again, it’s happening, it seems. I just saw it as I was walking in, so, it’s a terrible thing. And it’s a very, very terrible thing that’s going on in the world today. But it looks like another terrorist attack. And what can you say? It just never ends. We have to be strong, and we have to be vigilant, and I’ve been saying it for a long time.”
In Australia, Prime Minister Malcolm Turnbull has warned Australians to be wary of their surroundings overseas.
“Our prayers are with the family of the police officer that’s been killed, and we pray for a quick recovery for the police officer that’s been wounded. It has all of the hallmarks of a terrorist attack, but, at this stage, I’m advised that the French prosecutor is on the scene.”
Expressing solidarity with police, presidential candidates François Fillon and Marine Le Pen cancelled their final campaign events.
It is unclear how the shootings might influence the voting.
For weeks, former banker Emmanuel Macron and Ms Le Pen have been out in front in opinion polls.
But polls now show there is a chance any of four leading candidates could reach the second-round run-off on May the 7th.
SBS Europe correspondent Brett Mason is in Paris and says the shooting has heightened fears in a city already on edge.
“This comes just a day after what police described as an imminent terror attack was foiled in Marseille, the south-east of France, the port city where Marie Le Pen held her final campaign rally. In that attack that police believed was imminent, explosives, ammunition and weapons were uncovered by counterterrorism officers during a raid of a rented apartment. So this city was already on high alert. A state of emergency has been in place here for some time. Fifty-thousand police and military will be on the streets for the first round of that election on Sunday.”
France is at its highest possible level of alert since a string of attacks began in 2015, killing over 230 people up to now.