A Muslim butcher who could be stripped of his French passport over allegations of polygamy hit back on Monday, insisting that he had not broken the law.

Lies Hebbadj, an Algerian-born 35-year-old, has been at the centre of a political storm since last week when his wife complained that she had been fined for driving while wearing her "niqab" full-face veil.

The woman has refused to pay the fine and Hebbadj has taken her defence.

Interior Minister Brice Hortefeux suggested the man could lose his French passport, saying he was believed to have four wives who had borne him 12 children and that each was receiving welfare benefits.

But Hebbadj called a news conference on Monday to contend that, while he has several mistresses, he had not engaged in polygamy, which is illegal in France.

"As far as I know, it is not forbidden to have mistresses in France, nor is it forbidden under Islam," said Hebbadj, who runs a halal butcher shop in the western city of Nantes.

"Maybe under the Christian faith, but not in France," he added.

"If you lose your French nationality for having mistresses, then a lot of French men would have been stripped of their citizenship."

Immigration Minister Eric Besson is investigating whether Hebbadj should lose his French citizenship, which he acquired after marrying a French woman in 1999.