A Jewish man wearing a kippa skullcap was stabbed in the eastern French city of Strasbourg by a man who was arrested at the scene, police and Jewish community sources said.
The victim, who is in his 60s, was stabbed in the abdomen outside his home in the city's Jewish quarter, Strasbourg's chief rabbi Rene Gutman said.
His injuries were not life-threatening, Rabbi Gutman added. Police have not commented on the motive for the attack.
The rabbi cited witnesses as saying the victim's alleged assailant, who police said has a history of mental health problems, shouted "Allahu Akbar" (God is Greatest) at the time of the attack.
Rabbi Gutman also said the suspect had previously attacked a member of the local Jewish community in 2010.
Condemning the attack, he said it "in no way reflects the prevailing climate in Strasbourg," which has a large Jewish community.
The local prosecutor's office confirmed the arrest and said an investigation had been launched.
The attack comes as France reels from a string of jihadist attacks in the past year-and-a-half, beginning with the January 2015 killings in Paris at the satirical newspaper Charlie Hebdo and a Jewish supermarket.