A driver deliberately rammed his car into a police van as it drove down Paris' Champs Elysees avenue and was probably killed, police said, adding that no officers or bystanders were injured and the situation was under control.
The Paris prosecutor's counter-terrorism unit said it had opened an investigation into the incident, which occurred only a short walk away from the Elysees presidential palace and the U.S. embassy.
The car hit the front of the police van as it was overtaking it and caught fire, a police spokeswoman told reporters.
"It appears to have been a deliberate act on the part of the individual," said Interior Ministry spokesman Pierre-Henry Brandet.
Brandet told reporters the driver, who was armed, was "most likely dead", adding that it was difficult to say for sure while the area where he was lying was being checked for explosives.
A report on France's BFM TV said the man was known to security services and had been carrying a gas bottle in the car.
France has been on high security alert following a series of militant Islamist attacks in recent years, including the shooting of a policeman in an Islamic State-claimed attack on a police bus on the Champs Elysees in April.