The Islamic State group quickly claimed responsibility for the attack through its Amaq news agency, but investigations by authorities are still underway. The state of emergency in France is extended and extra protection, including robust barriers to prevent similar attacks, is put in place at major sites in France.
The gunman opened fire as the officers were guarding an area near the Franklin Roosevelt metro station on Thursday night.
She said France needed to "stop being naive and handle this this with a clear head and a firm grip".
The Paris prosecutor's office said the incident was being probed and that the investigation involved counterterrorism officials.
Officers searched the home of the dead attacker in a town east of Paris, a police source said.More news: Oil recoups losses, but USA oil output growth weighs
Australia's prime minister offered his country's prayers for the shot police officers and urged Australians in Europe to be on their guard.
France began picking itself up Friday from another deadly shooting claimed by the Islamic State group, with President Francois Hollande convening the government's security council and his would-be successors in the presidential election campaign treading carefully before voting this weekend.
Earlier Friday, interior ministry spokesman Pierre Henry Brandet told radio station France Info that a shotgun and knives had been found in the suspect's vehicle and that he had a long criminal record.
According to French media, the attacker served several years in prison for firing on police officers with a gun in the early 2000s.
"She won't be able to protect our citizens", Macron said of Le Pen.More news: Chelsea and Spurs get four players in team of the year
French interior ministry spokesman Pierre-Henry Brandet said a "weapon of war" was used against the officers.
Hollande said he was convinced the attack was "terrorist-related", adding that the security forces had the full support of the nation and a national tribute would be paid to the fallen policeman.
It is yet another assault on the French capital, which was hit by one of the worst terror attacks in recent history in November 2015 when bombers and gunmen killed 130 people.
Le Pen - narrowly trailing frontrunner Emmanuel Macron in opinion polls - said she would take steps to beat "Islamist terrorism" if elected, including introducing tougher immigration and border controls.
"I consider that in the context in which we live [today] there is no need to continue the electoral campaign tonight and tomorrow [April 20-21]", Fillon said during his speech on France 2 television. He called the attack "a bad thing", and said it was another example of the sort of violence that "never ends". "Will have a big effect on presidential election!" he said, breaking a silence over Sunday's vote in a tweet.More news: Tillerson accuses Iran of 'provocations'
Speaking during a televised debate around the time of Thursday's attack, Fillon said there was "no room for pursuing today or tomorrow an electoral campaign because first of all we have to demonstrate our solidarity with the police officers".
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