Three people were injured Saturday in a knife attack at Paris's Gare de Lyon railway station, a major travel hub, police said, adding that a suspect had been arrested and placed in detention.
The man, a Malian national, went on a stabbing spree at around 7:35 am (0635 GMT) at the station, which operates domestic trains as well as those heading to Switzerland and Italy.
One person suffered serious injuries to the abdomen while two others were lightly wounded, police said.
A terrorist attack has been ruled out at this stage and an enquiry launched.
Sources said the man appeared to be homeless and suffering from psychological problems.
Paris prosecutors said the suspect could have used a knife and a hammer that were under analysis.
"The suspect did not cry out (any religious slogans) during his attack," a police source said. "He presented the police an Italian driving licence", which gave his date of birth as January 1, 1992.
Passers-by overpowered the man before railway police arrived on the scene, the police source said.
"A thank you to those who overpowered the man who carried out this unbearable act," said Interior Minister Gerald Darmanin on X, formerly Twitter.
The attackers' motives remained unclear.
The Paris prosecutor's office launched an inquiry into the attack, while the national anti-terrorist prosecutor said it was observing proceedings at this stage.
The assault took place less than six months before Paris hosts the 2024 Olympics and and an expected 15 million visitors.
Each year more than 100 million passengers go through the Gare de Lyon, France's biggest mainline rail hub.
The area between halls one and three were temporarily inaccessible, rail operator SNCF said on X, formerly Twitter.
Services to the Paris region were delayed, the SNCF said, referring only to "an act of criminal intent".