Police arrested 62 people as dozens were seriously injured, including the far-right candidate himself after he was grabbed in a headlock during the violence at the Zenith arena in Paris on Sunday.
Mr Zemmour, 63, suffered a wrist injury as he tried to fend off a man who lunged from the crowd. The assailant was arrested and faces an assault charge, while Mr Zemmour was signed off work for nine days.
Seven anti-racism campaigners were among those wounded, including two with serious injuries, after they were set upon by Zemmour supporters inside the Zenith.
Videos showed the men and women from SOS Racisme being attacked after standing on seats while wearing T-shirts reading “No To Racism”. One of the clips shows a woman being repeatedly punched in the head by a man.
An investigating source said: ‘The 62 arrested face a variety of charges including violent disorder – some had turned up with metal bars and blocks of concrete to throw.
‘Mr Zemmour and the SOS Racisme demonstrators are among those who have made criminal complaints and police who attended the brawls have also filed detailed reports.’
Journalists, and especially TV crews, have also complained about being targeted by masked thugs at the rally.
Referring to the French department north of Paris, the source said: ‘Prosecutors from Seine-St-Denis have opened an enquiry.’
Mr Zemmour was placed in a headlock by an unidentified assailant, before making a speech in which he announced his new political party will be called ‘Reconquest’.
He is still hoping that he can provide a serious challenge to President Emmanuel Macron at next April’s elections.
On Monday it was announced that he had picked former army general Bertrand de La Chesnais as his campaign manager, Europe1 radio said.
It came after eight women reported sexual abuse by Mr Zemmour in the week that he announced his candidacy to become head of state. Mr Zemmour, a married father of three, has denied any wrongdoing and refuses to discuss the specific allegations.
Two weeks ago, Mr Zemmour failed in a legal bid to prevent Closer magazine from publishing details of his secret affair with his campaign manager Sarah Knafo, 28, who is expecting their baby in April.
Both Mr Zemmour and Ms Knafo had complained about ‘an invasion of privacy’, while Mr Zemmour’s 62-year-old lawyer wife, Mylène Chichportich, has yet to comment on the scandal.
Earlier this month, Mr Zemmour went on trial in Paris for calling child migrants ‘thieves, rapists and murderers’.
A verdict in the case for ‘complicity in provoking racial hatred and racial insult’ is expected in January.
Mr Zemmour, a print journalist turned television pundit, has already been convicted twice on similar charges, but is still riding high in opinion polls.
They suggest that he will go head to head with Mr Macron in the second round of the contest if he can beat far-right National Rally candidate Marine Le Pen in the first round.
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