France's National Front party is planning to sue Madonna this week after the pop singer projected the image of a Nazi swastika over the face of party leader Marine Le Pen during a Saturday concert in Paris.

Ignoring earlier threats of legal action by the far-right party, the controversy-courting pop singer performed her song Nobody Knows Me at Stade de France, while the superimposed image served as a backdrop during a video montage. The video had been shown at previous Madonna concerts, prompting outrage from several members of the National Front, including La Pen herself.

We understand how old singers who need to get people talking about them go to such extremes, she told the Daily Mail in June. If she does that in France, we will be waiting.

Wallerand de Saint-Just, a lawyer for the National Front, told the European press that legal action would be filed later this week, adding that projecting such an image of Marine Le Pen with a swastika implies that she is a Nazi.

The video in question was part of a montage that merged together images of various public figures, including Pope Benedict XVI and the toppled Egyptian president Hosni Mubarak. The image of Le Pen and the swastika, shown only for a few seconds, was followed by an image of Adolf Hitler. Audible gasps could be heard from the crowd when the image was shown, although the 53-year-old Madonna was unfazed by the reaction.     

Le Pen is the youngest daughter of Jean-Marie Le Pen, who founded the National Front in 1972. The 43-year-old former lawyer won 18 percent of the vote in the first round of the French presidential election in April, campaigning on a fierce anti-immigration policy and against what she calls the Islamization of France. In 2004, Le Pen's father was convicted of inciting racial hatred for making disparaging remarks against Muslims.

SOS Racisme, a French anti-racism organization, defended Madonna's public criticisms of Le Pen, commending the singer's resolutely anti-racist and feminist discourse.

Madonna also flashed her nipple and buttocks during Saturday's concert, although so far no one has threated legal action for that. The Paris show, seen by about 70,000 people, was part of Madonna's MDNA tour, which covers 30 countries and wraps up next year. Madonna is due to appear back in France on August 21, when she will play a concert in the coastal town of Nice.