"According to the results of our survey, individuals who identify as Muslim represent 5.6 % of the population
in mainland France.
This figure is an approximation, since the survey method inevitably produces margins of error, rendering it
difficult to obtain a precise and reliable estimate. The lack of official data, which would allow adjustments
based on socio-demographic information, further contributes to this lack of precision. Nevertheless, this
result reflects other existing estimates and therefore seems pertinent."
I still believe it tho, but the source isnt 100% reliable.