Police in Paris shot and wounded a man who attacked an officer outside the Notre Dame cathedral on Tuesday, the Paris police headquarters said.
Police had earlier said they were dealing with an incident in the courtyard outside the world-famous tourist site and warned the public to stay away.
Police sources said the officers shot at the man after he had threatened them with a hammer and refused to stop.
An Algerian student shouted 'this is for Syria' as he attacked a police officer outside Paris's Notre Dame Cathedral on Tuesday afternoon.
The man, whose name has not been released, was shot and injured by police after he used a hammer to attack an officer patrolling with two other policemen at 4.30pm local time.
One of the officers responded with two gunshots, which injured the assailant, who was carrying kitchen knives, a hammer and other unsophisticated weapons.
Paris prosecutors opened a counterterrorism investigation soon after the attack after the attacker said he was an 'ISIS soldier of caliphate', according to a probe source.
French Interior Minister Gerard Collomb says the attacker cried 'it's for Syria' as he went after officers patrolling an esplanade in front of the famous landmark.
One officer was lightly injured and the assailant was shot in the thorax, according to one source.
French counter-terrorism office opens investigation after Paris Notre Dame cathedral incident, prosecutor's office said later.
