"There was an attack inside a kosher supermarket in Sarcelles at lunchtime by two persons dressed in black who lobbed a device," said Richard Prasquier,
who heads France's main Jewish council CRIF.
There was no confirmation if the attack was linked to the film "Innocence of Muslims" which has triggered global protests since its release on the Internet or the publication of naked cartoons of Prophet Muhammad by a satirical French weekly on Wednesday.
"A Molotov cocktail was thrown at the shop," said Moshe Cohen-Sabban, a local Jewish community leader.
"Many people were going there to stock up for Yom Kippur which falls next Wednesday," he said.
Cohen-Sabban said there were no "special" religious tensions in Sarcelles, a working-class area with a population of about 60,000 and large numbers of Muslims and Jews.