A Libyan man in his 20s stabbed six people on Wednesday at the busy Gare du Nord train station in Paris before being shot and apprehended by police, police sources and officials said.
The Gare du Nord is a busy commuter hub which also serves as a departure point for trains to northern France, London and northern Europe.
Police were treating the stabbings as attempted murder, not as a terrorist attack.
The attacker's motive was not immediately clear, but a police source later identified him to AFP as a Libyan and subject to an expulsion order.
He had arrived in France three years ago and has a criminal record, the source said on condition of anonymity.
Of the six victims, one was seriously wounded in the attack at 6:42 am (0542 GMT), while the others sustained light injuries, prosecutors said.
The entire incident was over within two minutes, Interior Minister Gerald Darmanin told reporters at the scene.
The attacker used a sharp pointed tool in the attack, rather than a knife as initially suggested by police.
He sustained serious injuries to the chest and arm after police fired three rounds, leading him to be taken to hospital where he was fighting for his life, Darmanin said.
The police who intervened were off-duty officers in plain clothes who used their service weapons to stop the attack, he said.
The police officers "were returning from duty at police headquarters to take their train and go home, but they were armed", Darmanin said.
They were authorised to make use of their weapons although not on duty, he said.
One member of the border police deployed at the station was lightly injured.
"An individual injured several people this morning at the Gare du Nord," Darmanin had tweeted earlier.
"He was quickly neutralised. Thank you to the police for their effective and courageous response."
The incident caused delays to trains at the station in the early morning rush as police cordoned off the station and set up large white curtains around the attack scene.
But no services were cancelled, a spokesman for rail operator SNCF told AFP.
The Gare du Nord is one of the world's busiest train stations with 700,000 travellers per day.
It is the departure point for Eurostar and Thalys services to the UK, Belgium, the Netherlands and Germany.
France remains on a state of heightened security alert after a spate of deadly attacks by Islamist radicals, and others, since 2015.