France: 2.1 million Muslims (aged 18-50)
Translated from La Croix:
There are 2.1 million 'declared Muslims' aged 18-50 in France, far less than certain estimates advanced in the public debate, according to a new study by the National Institute of Demographic Studies (INED) and the National Institute of Statistics and Economic Studies (INSEE). The joint study on the diversity of populations in France, was published in October under the title "Trajectories and Origins". In France, a country which bans religious or ethnic statistics, it's usually estimated that there are 5-6 million Muslims.
Patrick Simon, sociologist, researcher at INED, and one of the authors of the study says that even adding those under 18 or over 50, you won't reach 5 million.
Patrick Simon explained that 'declared Muslims' are people who declare themselves Muslims, whatever their religion or practices. It is not an estimate based on country of origin or their parents. People who come from majority-Islam countries or born to parents from such countries are usually automatically considered Muslims, and this might partially explain the discrepancy. On the other hand, says Simon, their figures include converts.
According to the INED and INSEE study, Catholicism if the main religion in France with 11.5 million believers aged 18-50 (43% of the population), Islam is the leading minority religion with 2.1 million believers, followed by Protestantism (500,000), Buddhism (150,000) and Jews (125,000) [ed: the Jewish community says they have 500,000].