A police officer shot and wounded a man who attacked him with a hammer near Notre Dame Cathedral on Tuesday, Paris police and a police union official said.
Union official Cedric Michel said a man armed with a hammer went after the police officer, who was patrolling the esplanade in front of the world-famous cathedral known for its gothic architecture and gargoyles.
Michel said the attacker was "neutralised" by police.
A police spokesperson told The Associated Press that the officer used his weapon to shoot the assailant.
The spokesperson was not authorised to be publicly named.
He said the attacker was being taken to a hospital.
The incident happened around 1630 local time (1430 GMT).
Large numbers of police cars filled the area on the Ile de Cite island in the Seine River in the center of Paris as authorities urged people to stay away from the area.
Witnesses described a dramatic police operation in the tourist-filled area.
Lawrence Langner, a 73-year-old American visiting the neighbourhood just across the Seine River from the cathedral, told The Associated Press that he suddenly heard a commotion and two detonations like gunshots.
Journalist David Metreau, who said his office overlooks the square that fronts Notre Dame, tweeted that there were two blasts that sounded like shots.
He posted a photo of a body lying seemingly inert on the ground.
Others posted photos online of what appeared to be the interior of medieval Notre Dame, one of France's most-visited monuments.
Police said the operation was over about an hour after it started.
Paris remains under high security after a string of Islamic extremist attacks in recent years, including several targeting police officers and security personnel.
In April, an attacker opened fire on a police van on Paris' Champs Elysees, killing one and gravely wounding two others.
The attacker was shot dead by police.
The incident recalled two recent attacks on soldiers providing security at prominent locations around Paris, one at the Louvre museum in February and one at Orly airport in March.
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