Collomb also said that the Algerian student who attacked the officer with a hammer was also armed with knives.
There were unconfirmed reports that a man had been shot after attempting to attack a police officer. The spokesperson, who was not authorized to be publicly named, said the attacker was being hospitalized.
The attacker injured one officer before he was shot and injured by other officers.
The incident happened around 4:30pm. Visitors and locals alike scattered as gunfire rang out in the cathedral's broad plaza alongside the River Seine in central Paris.
Karine Dalle, a spokeswoman for the Paris diocese, told BFM TV that 900 people were inside the cathedral as police secured the area.
On Twitter, authorities announced that a police operation was underway and that people should avoid the area.
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American tourist Lawrence Langner, 73, told AP that he suddenly heard a commotion and two detonations like gunshots.
No group immediately claimed responsibility, but police searching the man's residence outside Paris found a declaration of allegiance to the Islamic State group, according to the Paris prosecutor's office. The police officers were praised online by Paris Mayor Anne Hidalgo, who tweeted her salute to their "courage".
They then checked his pulse and medics later came and took him away on a stretcher.
Notre Dame is one of the most-visited monuments in Europe, with an estimated 13.6 million visitors a year. She did not provide further details.
Paris is on high alert following a series of Islamic extremist attacks in recent years - with soldiers patrolling the city's streets along with police to protect tourist sites, government buildings and events.
Paris is still reeling from an April attack at the Champs-Elysees that left a police officer dead.
"Once again the police and forces of security, in our country like other countries in Europe, are vicitim of an attack in the name of a criminal ideology". He said Ikken's friends and family can not believe that he is suspected in the attack, saying: "it's not the person we knew".