A man stabbed a number of passers-by in Villejuif, about 8km (5 miles) south of the French capital, on Friday.
The attacker was chased by police after targeting people in a park. The motive for the attack was not clear.
Four people were believed to have been stabbed. Two were reported to have been seriously injured and had to be taken to a nearby hospital.
The attack took place at about 14:00 local time (13:00 GMT) and the targets appeared to have been chosen at random.
Police advised people to avoid the area near to the Hautes-Bruyères park moments after they received an emergency call.
The mayor of Villejuif, Franck Le Bohellec, said the deceased victim was a 56-year-old man who was out walking in the park with his wife and died trying to protect her.
In a tweet, the mayor offered his “sincere condolences to the family and loved ones of the victim”.
French counter-terrorism prosecutors said they were assessing the scene and authorities were trying to identify the attacker. Police said they were interviewing several witnesses.
France’s Deputy Interior Minister Laurent Nuñez, who later visited the scene, praised the police response, calling it an “extremely courageous act”.