A driver rammed a French police vehicle on the Champs Elysees on June 19.
The driver was arrested and police have the scene under control.
The area has been cordoned off. Police are using social media to tell people to steer clear of the area.
France has been on terrorist alert due to a series of attacks starting in 2015.
More than 230 French people have been killed by terrorists since 2015.
In April a lone gunman attacked a police van and killed one officer and wounded another before being shot to death himself.