In French, “laïcité” (laicism in English) is a concept denoting the absence of religious involvement in government affairs as well as absence of government involvement in religious affairs. French secularism has a long history but the current regime is based on the 1905 French law on the Separation of Church and State. During the twentieth century, it evolved to mean the equal treatment of all religions, although a more restrictive interpretation of the term has developed since 2004. The purpose of this study is to inquire into the issue of religion and secularism, which are the most important concepts in understanding contemporary French society, by associating them with the history of France. The concept of laicism has been gradually established in French society over the period of about four hundred years after the Renaissance, though it was decisively contributed to by the Dreyfus Affair in the late nineteenth century and the ensuing Separation of Church and State in 1905. Therefore, this study reveals the meaning of a confrontation between religion and laicism and that of the Dreyfus Affair in France and, furthermore, shows the way these meanings can be stretched by observing cases of Germany. Intellectuals, including André Malraux, made an early prediction that the twenty-first century would be an era of spirituality. And it is true that the religious issue is now at the heart of the most furious debate ever in the process of unifying Europe. Thus, the study also suggests the limits and possibilities of religion in modern society so as to develop new criteria to have a better understanding of contemporary European societies.