Two brothers, aged 18 and 23, were attacked while going to evening prayers at the Chaaré Tsion synagogue in Créteil just outside Paris.
Their two attackers, who had used knuckledusters, fled, one on foot, the other on a bike.
The victims were rushed to hospital, where one remained Sunday, although his life was reported not to be in danger.
“The attack is anti-Semitic, that’s undeniable,” the town’s Socialist mayor, Laurent Cathala, declared, although the localpréfecture said an anti-Semitic motive had not yet been established.
Jewish organisations were in no doubt, either, with the Crif umbrella group saying that the regularity of attacks has become “insufferable” and anti-Semitism watchdog BNVCA blaming a “worrying situation” on the “stigmatisation of Israel” and the “outbursts” of “so-called humourists, ideologists and extremists of the right and the left”.
On Saturday evening Interior Minister Bernard Cazeneuve ordered police to reinforce security for “estblishments connected to the Jewish religion and culture”.
French President François Hollande called for a mobilisation to ensure that “French Jews feel in perfect security”.
He also said that there was no doubt of the anti-Semitic nature of Saturday’s shootings outside the Jewish Museum in Brussels.
Belgian police are searching for the gunman who shot four people, killing three and leaving one in a critical condition.
One of the victims was reported to be a French woman and two have been identified as Israeli tourists from Tel Aviv.
Israeli Prime Minister Benjamin Netanyahu blamed the crime on “constant incitement against Jews and their state”, while Belgian Prime Minister Elio Di Rupo called it an “odious attack”.