The assailants, who were in a vehicle, slowed down while approaching the synagogue, fired the blanks, then sped off Friday, Le Parisien reported.
Moshe Cohen-Sabban, the president of the Val d'Oise Jewish community confirmed the shooting.
"It is an another act against the Jewish community. This is very worrying," he told Israeli broadcaster Arutz Sheva.
Police found nine blanks at the scene of the shooting, the Jewish Telegraphic Agency reported Sunday.
The incident came just hours after French anti-terrorism police announced they shot and killed a man wanted for the bombing of a kosher grocery store in Sarcelle last month. Police have arrested 11 men connected to the bombing and a domestic terrorist cell of alleged jihadists.
The suspects allegedly threw a small explosive device into the grocery store, injuring one person Sept. 19.