French police opened fire after a man tried to attack them with a hammer near the Notre Dame cathedral in Paris on Tuesday.
According to the Europe 1 television channel, the attacker attempted to assault three police officers on the forecourt of the cathedral. One of the officers shot the attacker twice, wounding him.
The assailant was reportedly hospitalized. The police urged the public to stay away from the area. Franceinfo said there might have been two explosions causing crowd movement.
The attack was declared an act of terrorism.
France has been on alert following the deadly attacks in November 2015 in Paris and Nice in July 2016.