A 29-year-old man has been killed and other four people wounded in a knife attack in the busy Opéra district of Paris on May 12.
According to witnesses, the suspect had shouted “Allahu Akbar” (God is greatest) before being shot dead by police.
ISIS later said one of its “soldiers” had carried out the attack.
France has been on high alert following a series of attacks in Paris and Lyon. More than 230 people have been killed by ISIS-inspired jihadists in the past three years.
Security forces have identified the attacker as being born in 1997 in the Russian republic of Chechnya, although he was not carrying any identification papers and has not been officially named. Chechnya is a republic in the North Caucasus region of southern Russia.
The republic declared independence in 1991 but Russian troops invaded in 1994 to quash it, sparking a decade-long conflict.
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Jihadist groups, including those aligned with ISIS, have long operated in the region.
The judicial source told French media the suspect had no criminal record and that his parents had been held for questioning. Another source told Reuters the suspect was not previously known to police.
The suspect is believed to be a French national.
This is thought to be the first time an assailant of Chechen origin has carried out a terrorist attack in France.
France is home to some 30,000 people of Chechen origin.
France’s Interior Minister Gérard Collomb said the man who died was a 29-year-old passer-by, but gave no further details.
The four who were injured have also not yet been named. AFP news agency, citing sources, said a 34-year-old man and a 54-year-old woman were seriously hurt, while a 26-year-old woman and a 31-year-old man were slightly wounded.
Gérard Collomb said none had life-threatening injuries.
The attacker began stabbing passers-by at about 21:00 local time.
Eyewitnesses described him as a young man with brown hair and a beard, dressed in black tracksuit trousers.
The attacker tried to enter several bars and restaurants but was blocked by people inside.
Police first tried to stop the assailant with a stun-gun before shooting him dead, nine minutes after he began the attack.
