A car slammed into soldiers on patrol outside Paris on Wednesday, injuring six people, two of them seriously, police said.
The vehicle took off after the incident, which took place at about 8:00 am (0600 GMT) in the northwestern suburb of Levallois-Perret.
Police described the incident as an "apparently deliberate act".
France has been under a state of emergency since November 2015 and has seen a string of attacks on security forces who have been regularly targeted, particularly those guarding key tourist sites.
An 18-year-old with a history of psychological problems was arrested on Saturday at the Eiffel Tower after brandishing a knife and shouting "Allahu Akbar" (God is Greatest).
He told investigators he wanted to kill a soldier, sources close to the case told AFP.
In February, a man armed with a machete attacked four soldiers on patrol at Paris's Louvre Museum, while in April another extremist shot and killed a policeman on the Champs Elysees.
In June, a 40-year-old Algeria doctorate student who had pledged allegiance to the Islamic State group attacked a policeman with a hammer outside Notre Dame cathedral.