A car deliberately hit a police van before bursting into flames on the Avenue des Champs-Élysées in central Paris, police officials say.
The driver, who was on a security watchlist, died in the incident. Police found a Kalashnikov rifle, handguns and gas bottles in the car.
“Security forces have been targeted in France once again,” Interior Minister Gérard Collomb said, calling it an “attempted attack”.
No-one else was hurt in the incident.
France is under a state of emergency after being hit by a wave of deadly terrorist attacks in recent years.
A policeman was shot dead and two others were wounded in an attack on the Champs-Élysées in April, just days before the first round of the presidential election.
Monday’s incident occurred a day after the end of France’s parliamentary elections, which saw President Emmanuel Macron’s party win a majority.
A white car could be seen standing in the middle of the empty avenue with one door open and sniffer dogs were sent in, the BBC’s Hugh Schofield reports from Paris.
Our correspondent says there are always many police and gendarme vehicles near the spot, as it is next to the local police station.
Bomb disposal experts were sent to the scene to inspect the vehicle, a Renault Mégane.
Mr Collomb, who visited the site, said weapons and explosives found inside “could potentially blow this car up”.
Reports say officers had to smash the car windows to pull the driver out.
Sources close to the investigation said the driver of the car had been on a security watchlist since 2015 for membership of a “radical Islamist movement”.
Police were reported to be searching the man’s home in the Essonne area south of Paris.
Police earlier warned people to respect a security cordon around the area.
The anti-terrorist section of the prosecutor’s office has opened up an investigation into the incident, which happened close to the Élysée Palace, the president’s official residence, and the US embassy.