A suspected attacker has been "downed" after driving into a police vehicle on the Champs-Elysees, officials in Paris have said.
Police said there were no casualties but a security operation is under way and people are being asked to avoid the area.
The suspect was seen lying prone on his stomach on the avenue. He has now been arrested and police say the situation is under control.
Authorities have said the driver rammed his car into a police vehicle.
According to police officials, the suspect was subsequently injured in an apparent clash with police.
The Paris prosecutor's counter-terrorism unit has now opened an investigation into the incident.