The saintly aura of Zinédine Zidane, France’s national football hero, has taken a knock this week amid allegations that he has been having an affair with a pop star.

A whiff of sacrilege has flavoured media coverage of the story, which has been confirmed by no one but threatens the image of the former French captain, an immigrant’s son celebrated for his quiet modesty and marital fidelity.

Zidane, 34, who has four children, retired after the World Cup in July from a career in which he is said to have earned more than £60 million. His head-butt on Marco Materazzi in the final against Italy was forgiven by the nation and he now earns his keep from advertising and as an ambassador for brands and causes.

Magazines and radio stations seized on the allegation that Zizou, as he is known, has been involved with Nâdiya, a 33-year-old soul music star, after Marc-Olivier Fogiel, a television presenter, asked her whether rumours about the pair were true.

Nâdiya, who is of Algerian origin, as is Zidane, angrily denied the tale, which had been circulating in Paris and on the internet for weeks. “This has to stop. I am a mother and I want people to respect my integrity . . . All those people can go and jump in the lake,” she told Fogiel. She had met the footballer only once, at a charity event, she said.

The chat show, on the M6 channel, enabled other media to bypass the usual French taboo over private life. They have resorted to an old ploy — devoting space to decrying the rumour while adding fuel.

“Fogiel — hands off Zidane,” screamed the front page of France Soir, which was relaunched this year as a British-style tabloid. Denouncing Fogiel’s “nasty tackle”, the newspaper said that the host had “asked a question which has frightened the media world for several months and which no one dared ask”.

The tale was then given a boost by Voici, a celebrity weekly. Its cover said that it was impossible that Nâdiya could be involved with “our national icon, whose discretion and legendary modesty matches his role as exemplary father and family man”. But Voici published without explanation photographs showing a disguised Zidane and Nâdiya entering the same Paris apartment building minutes apart last month. Nâdiya lives in the building, in the prosperous 17th arrondissement of Paris, according to Switzerland’s La Tribune de Genève.

Pressure rose yesterday when VSD, a news weekly, devoted its cover and three pages to a discussion of whether it was now acceptable “to attack Zidane’s image as a good father and protector of the family”. The magazine did not reach a conclusion, though it contrasted Zidane’s simple lifestyle to the opulent excess of David Beckham’s.

Zidane, who consistently polls as France’s most popular person, was last seen defending his family in the World Cup final in Berlin, where he head-butted Materrazzi for insulting his sister and mother. President Chirac led the nation in offering instant forgiveness.

Neither Zidane nor his wife, Véronique, have commented on the media storm. This week he was in Bangladesh on a trip organised by the Danone food company, which employs him as an ambassador. Yesterday the company dismissed the allegations as “speculation that lacks foundation or proof since the singer has denied it”.

Zidane today may face new questions over his private life when he visits a school in Chantilly, north of Paris. The town is just outside the band of northeastern banlieue, where there has been rioting over the past year. Zidane is regarded as the most successful role model for children from France’s poor immigrant housing estates.

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