Islamic State (IS) terror group has claimed responsibility for the shooting here in the French capital that saw a gunman open fire on a police van, killing one officer and injuring two, media reports said.
The terrorist network's news agency identified the attacker as Belgian man Abu Yusuf al-Baljiki in a tweet taking credit for the Thursday night attack, the New York Post reported.
IS said the assault was the work of one of its "soldiers".
Cops killed the shooter at the scene - and said he was someone they had previously flagged as an extremist.
At 9 p.m., the officers were stopped at a traffic light on the Champs-Elysees - a bustling boulevard popular with tourists and famed for its luxury stores and eateries.
The gunman pulled up next to the police vehicle, took out an automatic weapon and started shooting, New York Post quoted Interior Ministry Spokesman Pierre-Henry Brandet, Efe news reported.
"On the face of it, the officers were deliberately targeted," Brandet said.
Evidence and witness statements indicate that the attack was carried out by one man, Brandet said.
Paris police ordered the immediate evacuation of the Champs-Elysees and suspension of service at nearby metro stations.
The incident comes just three days before French voters cast ballots in the first round of the Presidential election.
Although the police have also confirmed the identity of the gunman, they are withholding his name to allow time to determine whether he had any accomplices, Paris Chief Prosecutor François Molins said at the crime scene.
Investigators have already searched the shooter's residence in suburban Paris.
French President Francois Hollande, who has convened a meeting of France's Defence Council for Friday morning, said he was convinced the shooting was an act of a "terrorist character."
"We have a great determination to battle terrorism here and everywhere our forces are engaged," the head of state said in a televised address.
"With regard to the security forces, the nation's support is total," Hollande said, adding that the government would organise a tribute to the slain policeman.
Authorities would remain on the highest alert, especially for possible threats to the election, he said.
France has been under a state of emergency since November 2015, when more than 130 people were killed in a single night by coordinated terrorist attacks in Paris.
Several of the candidates vying in Sunday's presidential poll issued statements of sympathy for the victims and their families, and some referred to the shooting as an act of terrorism.
Two Presidential hopefuls cancelled rallies scheduled for Friday.
US President Donald Trump, in comments prior to Hollande's televised address, said that the violence in Paris "looks like another terrorist attack."
"It never ends," he said during a joint press conference in Washington with visiting Italian Prime Minister Paolo Gentiloni, offering condolences to the French people.