SUMMARY: 1. Introduction - 2. The Vertical and Horizontal Influences - 3. Atheism, laïcité and Church - 4. Atheism, laïcité and Islam - 5. Today’s Popular Sources of Atheism - 6. Conclusion.ABSTRACT: With this article, the Author outlines the legal issues involving the atheism in France, analysing them in the light of the principle of laïcité. France has a long history of criticism of religion. Many philosophes of the Enlightenment, for example, have provided the classical writings in this field. In this sense, they were able to aliment two major streams of thought of the magmatic French atheism: one is based on the horizontal influences arising from the effect of increasing worldwide travel with the discovery that people do not necessary s...