Muslim rioters reportedly surrounded Don Yitzchak Abarbanel Synagogue in the 11th arrondissement of Paris on Sunday, and threw rocks into the house of worship. Large scale police forces were called to extricate the Jews.
Clashes erupted in Paris on Sunday as thousands of people protested against Israel and in support of terrorist groups in Gaza, where a six-day counterterror operation by Israel has left 166 dead.
Several thousand demonstrators walked calmly through the streets of Paris behind a large banner that read "Total Support for the Struggle of the Palestinian People".
But clashes erupted at the end of the march on Bastille Square, with people throwing projectiles onto a cordon of police who responded with tear gas. The unrest was continuing early Sunday evening.
In the northern city of Lille, meanwhile, between 2,300 and 6,000 people protested peacefully, according to differing figures provided by the police and organizers.
"I came to say no to this massacre," Amid Hamadouch, 30, told AFP at the Paris protest while it was still peaceful, with a sticker reading "Boycott Israel, Racist State" on his jacket.
"They are bombing innocent people. There are missiles being launched by Hamas, but the Israeli response is disproportionate. They are attacking the civilian population and not Hamas officials."
The crowd, very young, shouted slogans such as: "We Are All Palestinians!" and "Only One Solution, End the Occupation!".
Many protesters carried banners on which they had stuck photos taken from the Internet, reportedly showing Palestinian children killed or injured, houses razed to the ground or clouds of smoke emerging from bombed districts in Gaza.