Police arrested around 50 people at a banned pro-Palestinian protest in central Paris on Saturday that degenerated into clashes between demonstrators and armour-clad riot squads.
The rally, which gathered an estimated 5,000 people in the capital's Place de la Republique, dispersed after 90 minutes during which police who were targeted with rocks and other projectiles responded with tear gas.
The demonstration against Israel's Gaza offensive that has killed more than 1,000 Palestinians comes after other protests last weekend in Paris and a suburb that had also initially been banned descended into chaos.
Organisers of Saturday's protest had tried going to court to get the ban overturned, but they were unsuccessful and Interior Minister Bernard Cazeneuve warned that they would be held "responsible for any unrest... and liable to penal sanctions".
Of those arrested, some 30 people were detained pending decisions on whether to charge them, according to preliminary figures.
A police source said officers were under strict orders to take in people who made anti-Jewish statements or gestures.
The crowd had turned out with many holding aloft Palestinian flags and the red banners of the far-left New Anticapitalist Party that had called on people to defy the ban.
"Israel clear out of Palestine, the era of settlements is over", "Israel assassin, Hollande accomplice", "Israel, piss off, Palestine isn't yours" were some of the slogans shouted by protesters.
After an initial peaceful start, police began firing tear gas when some hooded protestors threw cans and other objects at them, and several journalists covering the event were roughed up.
Some 2,000 police were mobilised, and many of them were present on the square to stop the rally from moving on to other parts of the French capital.
Elsewhere in the country, nearly 10,000 people turned out in the eastern city of Lyon for a similar protest, though it was not banned and went off peacefully.
In the southern cities of Marseille and Nice, hundreds also turned up in support for Palestinians.
The Israel-Gaza conflict has stirred passions in France, home to the largest Muslim and Jewish communities in western Europe with around five million Muslims and half a million Jews.
While many protests around the country have gone smoothly, some recent demonstrations in Paris and the suburb town of Sarcelles have descended into chaos.
In Sarcelles last weekend, Jewish businesses were looted and in one violent Paris demonstration two weeks ago, protesters tried to storm two synagogues, raising concerns among the Jewish community about anti-Semitism.
But on Wednesday, several thousand people protested peacefully in Paris. Police said the rally attracted about 14,500 people, while organisers put the figure at 25,000.