France's justice minister faces calls to resign for refusing to sing the national anthem during an event to mark the end of slavery, saying it was like "karaoke".
Centre-right opposition party the UMP criticised Christiane Taubira for refusing to sing La Marseillaise on Monday. The far-right National Front party demanded that she quit her post.
After critics posted remarks on her Facebook page concerning the event at Paris's Luxembourg Gardens, Taubira hit back saying: "Some events are more a time for reflection than onstage karaoke."
Her comments only generated more outrage from the opposition. "What is most shocking is that she could justify herself not singing the national anthem by speaking of stage karaoke," said UMP leader Jean-Francois Cope.
"She is a minister. There are certain things one does not say, that one does not have the right to say, and I think I am among millions of French people who are deeply shocked," he said.
National Front leader Marine Le Pen said: "By comparing La Marseillaise to karaoke and refusing to sing it, Christiane Taubira has revealed her true colours, and those of the administration.
"This unacceptable gaffe is indeed symbolic proof of the highest order of their contempt for France, for its history and its people, who love to sing their anthem, and are proud of it."
Taubira was defended by the Socialist Prime Minister Manuel Valls, who said: "The country is bursting with these absurd controversies that waste time and divert our population from essential issues."
Public figures who fail to sing La Marseillaise have been attacked by the far right in the past.
The National Front called for the exclusion of Karim Benzema from France's national soccer squad after he said: "I cannot be forced to sing the Marseillaise."
Real Madrid striker Benzema was born in France to parents of Algerian descent.
Taubira, the most prominent black person in French public life, is a regular target for France's right-wing opposition, partly as a result of her having been the main government architect of last year's legislation to legalise gay marriage, and partly because she is seen as being soft on crime.
The hostility towards her has, at times, spilled over into overt racial abuse, with the minister having been the subject to a string of "banana" slurs over the last year.
"It's been two years that this has been going on," she said on television over the weekend. "Perhaps these people that do this to me could consider finding one month with one week where they don't launch a polemic against Taubira."