Madonna has adopted many personas through the years but that of political activist is a new one.
The American singer has reportedly insulted France's far-right National Front party after one of her pop videos appeared to depict its leader, Marine Le Pen, with a swastika on her forehead.
Another image resembling Adolf Hitler followed that of Ms Le Pen in the video accompanying the song Nobody Knows Me.
The video was shown at Madonna's concert at the Stade de France in a Paris suburb on Saturday and has been shown at previous concerts on the singer's 30-nation MDNA world tour.
National Front spokesman Alain Vizier said on Sunday that the party would file a complaint in a French court next week for "insults".
The vice-president of the party Florian Philippot described the slur as "just another provocation" and suggested it was a stunt "so that people will talk about her".
He said: "Marine Le Pen will defend not only her own honour but her supporters and the millions of National Front voters."
Ms Le Pen won 18% of the vote in the first round of France's recent presidential election and has been trying to shed the National Front's image as racist and anti-Semitic.