A 31-year-old French woman was fined for wearing a niqab while driving, a further sign of France's bid to clamp down on the face-covering Islamic veil which President Nicolas Sarkozy says demeans women.

The unnamed woman told LCI television on Friday that police stopped her last month while she was driving in the city of Nantes, near the French Atlantic coast.

She was wearing a black niqab that covers the face but leaves the eyes exposed. Police handed her a 22-euro ($29) fine, saying her clothing posed a 'safety risk' to her driving.

'My eyes were not covered. I can see just like you and my field of vision was not obstructed,' said the woman, who did not give her name. She said she would appeal against the decision.

The incident has now reached ministerial level.

On Friday, the Interior Minister requested the Immigration Minister look into revoking the French nationality of the driver's husband as information he possessed showed the man was a polygamist married to four women with 12 children.

'Each of these women benefit from single parent benefits and ... each one wears the full veil,' Interior Minister Brice Hortefeux said in the letter seen by Reuters, adding he had asked the local authorities to look into possible benefit fraud.

'I would appreciate it, should these factors prove true, if you could study whether this individual could be stripped of the French nationality,' Hortefeux said, addressing Immigration Minister Eric Besson.

According to sources, the woman's Algerian-born husband acquired French nationality in 1999.

The controversy comes just two day's after Sarkozy backed a strict public ban of the veil, commonly referred to in France as the burqa, eschewing more moderate proposals that focused on limits in state institutions such as schools and town halls.

Polls have shown while most French voters back a ban, legal experts have warned it could violate the country's constitution.

France's highest court has warned the government that a complete ban could be unlawful. – Reuters