France stepped up security on Monday, a day after protesters demonstrating against Israel's operation in Gaza tried to storm two Paris synagogues.
According to the AFP news agency, President Francois Hollande warned that he did not want to see "the Israeli-Palestinian conflict imported into France" after two Jewish men were hurt in clashes that erupted on Sunday.
Several thousand demonstrators joined in the Paris protest on Sunday, with violence breaking out at the end of the march on Bastille Square as people threw projectiles onto a cordon of police who responded with tear gas.
A small group tried to break into two synagogues in central Paris, a police source told AFP.
The Jewish men were not badly hurt. Six policemen were also injured.
In his traditional Bastille Day television interview, Hollande said he did not want the "consequences" of the conflict playing out in France, and would not tolerate such attacks.
"The conflict between Israel and Palestine cannot be used as an excuse for anti-Semitism," the President said, according to AFP.
Joel Mergei, president of the Central Israeli Consistory, the top Jewish religious authority in France, said the violence represented a "new low" after an earlier petrol bomb attack on a synagogue in the suburb of St Denis.
France has the largest Jewish and Muslim communities in Europe, and there has been an marked upsurge in anti-Semitic attacks in recent years.
Serge Ben Haim, one of the leaders of the Jewish community in Paris, said on Monday that Sunday’s incident was a watershed occurrence.
“What existed in the past can no longer continue. We could have had something like Kristallnacht,” he told Army Radio, referring to the infamous “night of broken glass” in 1938, when Nazis swept through Jewish towns and neighborhoods throughout Germany and Austria, murdering some 500 Jews, burning homes and synagogues, and destroying shops.
“They decided to advance in large numbers toward the synagogue, and that was where they met our youths who volunteer to protect Jewish places, and then the police,” he recalled.
A wave of anti-Semitic violence has rocked French Jewry in recent weeks. In June, a gang of 20 attackers reportedly assaulted visibly Jewish students wearing kippot (yarmulkes) at a local library in the capital city of Paris.
In May, two Jewish men were attacked outside Paris as they were leaving a synagogue.
The men were stabbed just hours after a gunman entered the Brussels Jewish Museum and began shooting, killing three people - including two Israelis - and critically wounding another.