A similar show of support was also held outside the Israeli Consulate in New York.
"The Hamas charter calls for destruction of Jews," read some of the signs raised by the French protestors.
Addressing the crowd, the president of the Israelite Consistory of France, Joel Mergui, likened "terrorism that wants to kill in Israel" as "the same that attacks Jewish children in France."
Support for Israel in Paris and New York (Video: Reuters)
Hundreds of riot police surrounded a group from the militant Jewish Defense League and ordered them to lower flags that bore a Star of David and a clenched fist.
A main axis was blocked off for the demonstration just off the famed Champs-Elysees Avenue, and riot police vans lined neighboring streets.
'Stop Palestinian terrorism.' NY protest (Photo: Reuters)
"Everyone seems to forget what Israel has been going through, years of rockets," said one of the protestors. "Every state has a natural right to defend itself. I am French and I'm Jewish and clearly I take an interest in what is happening."
Ariel, another protestor, said: "We feel close to them because they haven't done anything for which they deserve what they're going through. When missiles are fired on you while you're in school, at home or at a restaurant, it's very scary. We want to tell them that we support them with all our hearts."
Past Middle East tensions have impacted on France, which has Western Europe's largest Jewish and Muslim populations, and boosted anti-Muslim and anti-Semitic incidents.
Show of support in Paris (Photo: AFP)
'Hamas charter calls for destruction of Jews' (Photo: AP)
'Israel's war is France's war' (Photo: EPA)
'We stand with Israel' (Photo: EPA)
'Israel, we're all united' (Photo: AFP)
A protest organized by Jewish organizations was held in New York. Michael S. Miller, CEO of the Jewish Community Relations Council of New York, said during the event: "The purpose of this gathering is to express the unequivocal support for the State of Israel among New York's political, communal, ethnic and faith leaders.
"The flagrant and unprovoked violence emanating from Gaza must immediately come to an end. Until then, we wholeheartedly support Israel's right to defend herself."
He added that any moral comparison between Israel's actions and Hamas' actions should be strongly rejected.
The JTA news agency reported that the Jewish Federations of North America have committed $5 million in assistance to the Jewish Agency's Israel Terror Relief Fund for the immediate needs of the people living under fire.
Organizations representing Orthodox Judaism – the Rabbinical Council of America, the Orthodox Union and the National Council of Young Israel –called on "all Jews to increase their Torah study as spiritual support and merit for those Israeli soldiers and civilians on the front line of battle."
The RCA instructed its members to hold special classes and lectures in their communities "dedicated to the support of the IDF and the State of Israel," JTA reported.
The Associated Press contributed to this report