Two British tourists were among seven wounded after a man attacked people with a knife and iron bar in Paris.
People tried to hold back the attacker by throwing pentanque balls, according to a witness.
The suspect - who was subdued by the public and unconscious when police arrived - is reported to be an Afghan national.
The attack happened on Sunday night on the banks of the Bassin de la Villette, a popular canal area close to Gare de l'Est.
Youssef Najah, 28, said he saw a man running with a knife about 25-30 cm (10-11 inches) long.
"There were around 20 people chasing him. They started throwing petanque balls at him," Mr Najah said.
"Around four or five balls hit him in the head, but they weren't able to stop him."
One victim said the attacker's "eyes were bulging as if he was in a trance".
Pouiti Mari-Bornand, 26, told Le Parisien he was sitting by the canal with his feet in the water when he heard screams and saw a man hit a woman with an iron bar.
He said the man then chased and attacked him as others screamed warnings.
Police did not give any information about the victims but said they included two British tourists.
French broadcaster BFMTV and Le Parisien reported that one of the Britons was stabbed in the head and that the pair had apparently not understood the warnings being shouted.
The Foreign Office said it was aware of the reports, but offered no further information.
The attacker was eventually overpowered and was unconscious when officers arrived, police said.
They said four people were in a critical condition, while a judicial source said there was "no initial sign" the attack was linked to terrorism.