A political row over the case of a French woman fined for driving in an Islamic veil gathered pace Sunday as a leading Muslim scholar and a French far-right leader both weighed in.

With the government planning to ban the full Islamic veil in public, the fining of the French woman in Nantes took a political turn when a minister threatened to punish her Muslim husband for offences including polygamy.

The woman has challenged the fine as a breach of her human rights.

Tariq Ramadan, a professor of Islamic studies at Oxford University, said that the move by French Interior Minister Brice Hortefeux to punish the woman's husband "betrays the values of France".

"To be polygamous is illegal... that is the law that says that. But since when has a minister been able to say that they will take away his nationality?" Ramadan told around 1,000 people at a conference the Arrhama mosque in Nantes.

Hortefeux had written to Immigration Minister Eric Besson asking him to look into allegations the woman's husband may belong to a radical group and may be a polygamist with four wives and 12 children and guilty of welfare fraud.

He said the man could be stripped of his French nationality if they proved true.

Swiss-born Ramadan, who had a Bush-era visa ban lifted by the United States earlier this year, hailed the Muslim community of Nantes for refusing to react to "provocation" over the issue.

Mourad Sandi, an official at the Arrhama mosque, said the affair had been given too much attention in the media. "I am not sure the subject merits our discussing it, we do not want to add fuel to the fire," he said.

But the collective of Nantes mosques said in a statement that they were "worried by this systematic stigmatisation which goes against the values of the Republic".

The association "considers that the stopping of a driver is a judicial procedure and is angry at how such an event has been turned into being all about Islam."

Meanwhile French far-right leader Jean-Marie Le Pen told local media it was "scandalous" that the man's alleged wives were receiving family benefits and said the potential stripping of the man's French citizenship was "normal".

But on the veil ban, Le Pen said the issue was "covering up more serious problems" and there was "no need for a law".

President Nicolas Sarkozy's government said last week it would push ahead with a ban on wearing a full-face veil in public, despite a warning from state legal experts that such a law could be unconstitutional.

In this context, the Nantes incident gained political momentum and dominated the news this weekend.

Besson, the immigration minister, said Sunday that the procedure to strip the man's French nationality could not start unless he was convicted of illegal activity, adding that it would "probably" be difficult to prove polygamy.

"There will have to be an inquiry first of all, then possibly a decision by the courts, and only then possibly the forfeiture (of his citizenship)," Besson said in a televised debate.

Hortefeux's move has been praised by members of the right-wing governing UMP party and criticised by opposition figures such as Communist Party leader Marie-George Buffet, who called it a "bad-taste political operation".

The state prosecutor in Nantes, Xavier Ronsin, told AFP on Sunday that so far no charge had been lodged against the husband but an investigation could be launched if there were grounds to suspect fraud.

Hortefeux wrote that the husband was born in Algeria and acquired French nationality by marrying the woman in 1999.

Polygamy is a jailable offence in France, but only civil marriages conducted by a state official count -- not religious marriage ceremonies.

It was not clear on Sunday whether the veiled woman's husband was joined to his other alleged wives by civil marriage or by religious rites such as Muslim weddings.