Statistics
The French government does not keep statistics as to religion, nor to ethnic groups or political affiliation. However, some unofficial survey estimates exist from CIA and poll:
* The 2003 CIA World Factbook lists the religion of France as: Roman Catholic 83-88%, Protestant 2%, Jewish 1%, Muslim 5-10% (mostly, North African immigrants and their descendants), unaffiliated 4%. The sources for this data are unclear.
* In a 2003 poll 41% of the respondents said that the existence of God was "excluded" or "unlikely". 33% declared that "atheist" described them rather or very well, and 51% for "Christian". When questioned about their religion, 62% answered Roman Catholic, 6% Muslim, 2% Protestant, 1% Jewish, 2% "other religions" (except for Orthodox or Buddhist, which were negligible), 26% "no religion" and 1% declined to answer. The discrepancy between the number of "atheists" (33%) and the number of with "no religion" (26%) may be attributed to people who feel culturally close to a religion, follow its moral values and traditions, but do not believe in God.
* A December 2006 poll by Harris Interactive, published in The Financial Times, found that 32% of the French population described themselves as agnostic, a further 32% as atheist and only 27% believed in any type of God or supreme being.[2]
* A January 2007 poll found that 51% of the French population describe themselves as Catholics, 31% as atheists, 4% as Muslims, 3% as Protestants and 1% as Jews.[3]
Gallup International reports that 15 percent of French citizens regularly attend religious services, compared to 10 percent of UK citizens and 57 percent of American citizens.
http://en.wikipedia.org/wiki/Religion_in_France#Statistics