Over half of France's young Muslims put sharia law ABOVE their own country's

Thirty years ago, that figure was just 36 per cent.

The youths have been found to back religious rules on halal slaughter, marriage and inheritance.

While further data revealed that more than one in three young French Muslims sympathise with Islamist ideology, over double the number who expressed such views in 1998.

Francois Kraus, a historian and author of the study, said the study hinted at "a process of re-Islamisation" driven by younger generations.

He said: "This survey very clearly outlines the profile of a Muslim population increasingly structured around rigorist religious norms and tempted by an Islamist political project.

"Fundamentalism has won over the minds of more than one in three Muslims.

"It also translates into a very violent gender separatism. You have 45 per cent of young Muslims who refuse to 'faire la bise'," referring to the French custom of kissing the cheek as a greeting.

Multiple topics under Sharia are incompatible with French law, including unequal inheritance for women, corporal punishment for crimes, and strict restrictions on freedom of expression and sexuality.

The poll also indicated a shift in the religious actions of Muslims in France.

Some 40 per cent of French Muslims attend mosques, in comparison to just seven per cent in 1989.

In the same time period, strict fasting during Ramadan jumped from 51 to 83 per cent, and the proportion of young women wearing the veil has nearly tripled.

Similarly, in comparison to the 41 per cent in 1998, only 12 per cent of young Muslims now want Islam to adapt to modernity.

France is home to Europe's largest Muslim population, accounting for seven per cent of the people in the nation, up from below one per cent 40 years ago.

The integration of Muslims has been a lightning rod topic in France in recent years - especially in the wake of 2015's deadly terrorist attacks in Paris.

In May, President Emmanuel Macron received a controversial report which warned that Islamist networks, particularly those associated with the Muslim Brotherhood, were carrying out "entryism" by infiltrating schools, associations, and local institutions to "change them from within".

In July, Mr Macron announced increased surveillance and financial sanctions among other "restrictive measures" to better fight Islamism.

Pierre-Romain Thionnet, a politician from the populist National Rally, said the study showed Muslim youths were "not assimilating but re-Islamising".

However, Chems-Eddine Mohamed Hafiz, the rector of the Grand Mosque of Paris, said the poll reflected increasing anger among young Muslims - 66 per cent of whom, according to a previous poll, claimed they had been victims of racism.

He told Charlie Hebdo magazine: "As an imam, I talk to a lot of young people. They tell me that they are constantly stigmatised."