There are over 2,000 places of Muslim worship in France. Many of them follow a specific interpretation of Islam linked to countries such as Morocco or Algeria.
But some of them are unaffiliated. This has raised government suspicions about their activities.
French police are carrying out an unprecedented inspection of 76 of these mosques as part of a move against so-called 'religious separatism'.
Interior Minister Gerald Darmanin told French newspaper Le Figaro that this lack of affiliation has allowed authorities to identify separatist mosques that have "declared war against the Republic".
Watch Euronews' International correspondent Anelise Borges' report in the video player above.