Police have shot a man who attacked an officer with a hammer outside the Notre-Dame cathedral in Paris.
The man shouted “this is for Syria” during the attack, the interior minister said. Prosecutors have opened a terrorism investigation.
The officer suffered minor injuries. The suspect was wounded in the chest when another policeman opened fire.
Tourists fled for cover as the attack unfolded. Hundreds of people were in the cathedral at the time.
France is in a state of emergency since attacks by jihadists in Paris killed 130 people in 2015.
It is part of the US-led international coalition against IS and has conducted air strikes against militants in Syria.
The assailant on Tuesday afternoon carried kitchen knives and the identity card of an Algerian student, French Interior Minister Gérard Collomb said.
The man, who was being treated in hospital, has not been named.
The terrorist spotlight has swung to Britain, but no-one in France is under the illusion that the country is safe. Squads of soldiers with automatic weapons at the ready are a regular sight on the streets of Paris. France remains a favourite target for the propagandists of so-called Islamic State.
What intrigues is the similar character of four recent attacks in Paris: at the Louvre in February, where a man attacked a soldier with a machete; at Orly airport in March, where an attacker was killed after trying to take a gun from a soldier; on the Champs-Elysées last month, where a gunman killed a policeman before himself being killed; and now this.
Different from the recent UK atrocities – and the earlier French attacks in Paris and Nice – none of these recent French attacks was against random targets. They were all conducted by lone men. And they were all against clearly identified symbols of the state.