Three people were wounded in a hammer and knife attack at the Gare de Lyon railway station in the centre of Paris on Saturday, police said.
One of the victims is reported to be in a serious condition and two others sustained light wounds in the attack, which took place at 8am local time.
The knifeman was overpowered by bystanders before station security guards detained him, according to local media reports. He was then arrested.
“Thank you to those who controlled the perpetrator of this unbearable act,” said Gérald Darmanin, the interior minister.
The victims were being taken care of by the emergency services, said Mr Darmanin.
Paris police have said the incident was not a terror attack.
“The suspect did not cry out (any religious slogans) during his attack,” a police source told the AP news agency. “He presented the police with an Italian driving licence”.
The attacker showed signs of having a mental disorder, Laurent Nuñez, the head of police in Paris, told reporters. “We found medicine on him which suggests he was undergoing treatment.”
It was later confirmed that the man was carrying a hammer as well as a knife during his spree.
The suspect has an Italian residence permit and was in France legally.
Police did not confirm reports in the French media that the suspect was originally from Mali.
SNCF, France’s national railway company, said that parts of the station were closed on Saturday morning due to the police operation, causing delays to some connections.
“Traffic is slowed down between Paris Gare de Lyon and Montargis and between Gare de Lyon and Montereau,” the company stated.
Gare de Lyon is the second busiest station in Paris after the Gare du Nord and serves links to the south of the country. It handles close to 150 million passengers a year.
Paris has been the scene of several similar attacks in recent years, with Islamist extremists attacking innocent bystanders.
In December, a man wielding a knife and a hammer killed a German tourist and injured a British bystander near the Eiffel Tower.
The attacker was heard to scream “allahu Akbar” during his assault. French president Emmanuel Macron later described it as a “terrorist attack.”
In January of last year, a man stabbed and injured six people at the city’s Gare du Nord station.
That assault was stopped by two off-duty police officers.