As many as 62 police officers were injured and 81 people were arrested at so-called "freedom marches" across France on Saturday, according to the country's Interior Ministry.
Demonstrations took place throughout the country against a controversial new bill that would ban police images and increase surveillance.
The ministry said 23 of the arrests took place in Paris and the other 39 in other locations.
Several videos published on social networks appeared to show police officers being beaten by demonstrators at the events.
Two people that took part in protests that were not in the capital reported they had been injured to the General Inspectorate of Police (IGPN), police said.
Syrian freelance photographer, Ameer al Halbi, 24, who was covering the demonstration was injured in on his face, according to AFP.
Reporters Without Borders' secretary-general, Christophe Deloire, denounced what he said was "unacceptable police violence" against Halbi.
A total of 133,000 people, 46,000 of them in Paris, took part in the protests, according to the Interior Ministry. Organisers put the figure at 500,000, with 200,000 of them in the capital.
What were demonstrators speaking out against?
The French parliament is currently examining article 24 of the National Security bill, which proposes criminalising the filming and publication of images of on-duty police officers.
Media groups in France say it could impact journalists covering police operations, while other critics fear it's intended to dissuade citizens from holding the police accountable.
The organisers of the protests claim 500,000 took to streets throughout France, reporting 200,000 demonstrators in the capital Paris alone.
The StopLawSecurityGlobal coordination, which includes journalists' unions and human rights groups, also denounced violent scenes that it said took place in Paris and Lyon after the end of the demonstration.
The protests came after video images of three police officers beating a black music producer inside his studio in Paris went viral this week, causing an outcry that saw politicians, footballers and millions of social media users express their disgust.
But supporters of the law, above all Interior Minister Gerald Darmanin, say it is necessary to protect the identity of law enforcement officers who are at risk of harassment, threats and violence.
On Thursday, French Prime Minister Jean Castex said the government would review the wording of the draft law following the new scandal over police brutality.
In Paris, thousands gathered in the Place de la Republique carrying flags and banners that denounced police violence, demanded media freedom and called for the Interior Minister's resignation.
There were some scuffles between protesters and police in the surrounding streets.
Thousands turn out in Nantes
Police said around 3,500 people took to the streets of the French city of Nantes on Friday night to demonstrate. Joint trade unions say the figure was between 6,00-7,000.
Demonstrators carried banners and placards reading "defence of individual and collective freedoms," "no to the proposal for a comprehensive security law," and "violence, the last refuge of incompetence," as well as "not seen, not taken."
The march began calmly, but scuffles broke out for an hour and a half from around 7:30 pm when police used tear gas to dispersed the crowd.
"I am not criticizing all the police officers, of course, we need a respectable police force, we need a trusted police force, but they have to clean up," explained Camille, a 56-year-old demonstrator from Nantes.
"I am very angry," he added. "To all the police officers who are doing their job correctly, I wish them good luck in this police force, which is drifting towards unacceptable things."
Among the slogans chanted were: "Liberty, liberty, liberty," and "police everywhere, justice nowhere," as well as "everyone hates the police."
Officers said they arrested 17 people, including six before 5.30 pm when the police asked protesters to open their bags when they arrived at the assembly point.
"Justice must quickly shed light on this police violence," tweeted the mayor of Nantes Johanna Rolland, in reaction to the images of the beatings of the music producer in Paris.
"It is also urgent to create an independent control and sanction authority, in place of the IGPN (General Inspectorate of the National Police)," said Rolland.
In the face of criticism, the government added an amendment to the bill, specifying it "will only target images aimed at harming officers' physical or psychological integrity."
After clearing the lower house, the draft security law will now need to be approved by the Senate.
Some experts believe it could also face censure from France's constitutional court.