Just under 30 per cent of French Muslims favour sharia law over secular laws in France, according to an Ifop poll published by the weekly Journal du Dimanche.
Asked if they considered the Islamic legal and moral code of sharia to be more important than the French Republic's laws, 29 percent of respondents answered "yes".
The poll found that 20 per cent of male Muslim respondents and 28 percent of female Muslim respondents were in favour of the face veil, the niqab, and the burqa.
Meanwhile, 60 per cent said they were in favour of letting girls and women wear a head scarf at schools and universities, which is forbidden at France's secular public institutions.
Deadly attacks by Islamist militants – including bombings and shootings in Paris which killed 130 people last November, and, in July, a truck attack in Nice killing more than 80 and the murder of French priest Jacques Hamel in his Normandy church – have raised tensions between communities in France.
French Muslim leaders last month said that decisions taken by some municipal authorities to ban the body-covering swimwear, the burkini, could lead to further stigmatisation of Muslims.
The Ifop poll contradicted previous estimates which said Muslims made up to 10 per cent of France's population of some 65 million. It said Muslims represented 5.6 per cent of the country's citizens aged 15 and over and 10 per cent of under 25s. It said 84 per cent of France's Muslims were under 50.
It can be difficult to establish the religious background of French citizens because the country's secular laws forbid the collection of data on religion and ethnicity.
There are also many people who may be of Muslim descent, but do not necessarily consider themselves Muslims.
The poll, commissioned by the think-tank Institut Montaigne, was conducted by phone between April 13 and May 23 among 1,029 people aged 15 and older who were of Muslim faith or culture, extracted from a sample of 15,459 people.
Additional reporting by Reuters
