The motives of the gunman were unclear, with two of the four injured left in a serious condition in rue d’Enghien in the trendy 10th arrondissement.

“The shooter has been arrested with his weapon. The danger is over,” a police source told AFP. “His motives remain unknown at this stage.”

The shots shortly before midday (1100 GMT) caused panic in the neighbourhood, a bustling area of shops, restaurants and bars.

Resident Emmanuel Boujenan told AFP that the man had been arrested in a hair salon.

“There were people panicking, shouting to the police and pointing to the salon ‘he’s in there, he’s in there, go in’,” he explained.

He said he saw two people on the floor of the salon with leg wounds.

A shopkeeper in the area told AFP on condition of anonymity that she heard seven or eight shots, saying “it was total panic. We locked ourselves inside.”

The Paris prosecutor’s office said an investigation had been opened and that “a man aged between 60 and 70 has been arrested and is in custody”.

“His identity is in the process of being checked,” it added.

News of the shooting set nerves jangling in a city that has been repeatedly targeted by terror groups since 2015.

Paris is also the scene of occasional outbreaks of gang violence.