The French government has admitted its security measures had been "insufficient" to stem an arson and looting rampage by black-clad anarchists during a "yellow vest" protest along the famous Champs-Elysees in Paris.
Police had appeared overwhelmed on Saturday as demonstrators ran amok on the avenue, with retailers there saying some 80 shops and businesses were vandalised.
Prime Minister Edouard Philippe acknowledged Sunday there had been security "flaws" which needed to be rectified.
"Analysis of yesterday's events highlights that the measures taken were insufficient to contain the violence and prevent wrongdoing" by the rioters, the premier's office said, adding that Philippe was due to meet President Emmanuel Macron on Monday morning.
Already under political pressure, Macron -- who cut short a skiing trip to rush back to the capital for a crisis meeting late Saturday -- has vowed "strong" action.
Retailers have expressed dismay over the 18th consecutive weekend of potent anti-government rallies. Saturday's turnout was characterised by a sharp uptick in violence after weeks of dwindling turnout.
"It feels like this will never end," said Emir Fatnassi whose shop front on the Champs-Elysees was smashed in by rioters.
"You can protest but why destroy everything?... Repairing the windows will cost at least 25,000 euros, and an important part of merchandise is gone."