Islam in France

Islam is the second-most widely professed religion in France behind Catholic Christianity by number of worshippers. With an estimated total of 5 to 7 percent of the national population, France has the largest number of Muslims in Western Europe.

The majority of Muslims in France belong to the Sunni denomination. The vast majority of French Muslims are of immigrant origin, while an estimated 100,000 are converts to Islam of indigenous ethnic French background. The French overseas region of Mayotte has a majority Muslim population.

Due to a law dating from 1872, the French Republic prohibits performing census by making distinction between its citizens regarding their race or their beliefs. However, that law does not concern surveys and polls, which are free to ask those questions if they wish. The law also allows for an exception for public institutions such as the INED or the INSEE whose job it is to collect data on demographics, social trends and other related subjects, on condition that the collection of such data has been authorized by the CNIL and the National Council of Statistical Information (CNIS^[]).

A study from INED and the INSEE in October 2010 concluded that France has 2.1 million "declared Muslims" aged 18–50 including between 70,000 and 110,000 converts to Islam.

According to the French Government, which does not have the right to ask direct questions about religion and uses a criterion of people's geographic origin as a basis for calculation, there were between 5 and 6 million Muslims in metropolitan France in 2010. The government counted all those people in France who migrated from countries with a dominant Muslim population, or whose parents did. Only 33% of those 5 to 6 million people (2 million) said they were practicing believers. That figure is the same as that obtained by the INED/INSEE study in October 2010.

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