Local media say the 39-year-old lived in the city’s suburbs, and had been seen as a potential Islamist radical.
French police are also hunting for a man who has been identified by Belgian security services, an interior ministry spokesman says.
He had also wounded two police officers.
President François Hollande is to chair a security cabinet meeting, as France readies for Sunday’s presidential poll.
Mr 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.
So-called Islamic State (IS) said one of its “fighters” had carried out the attack.