The bloody First and Second World Wars awakened the dream of a cross-border peaceful territory supported by the Christian community principles of the clerics founding the first universities in the Middle Ages. Since the 1950s the European Union has been built up from six member states to reach twenty-seven, with more associate members. But increasing immigration, in particular from Islamic countries, has challenged the Western democratic paradigm. Multicultural state policy aiming to respect populations with an immigrant background was rejected by political leaders after terrorist attacks and other critical incidents. At the same time, Europe's historically established churches promoted the idea of a declaration in the preamble to the Constitution, stating that Europe's values are rooted in Christianity. Are religious wars coming again in Europe and breaking the ideal of peace, as in the sixteenth century? What is the democratic answer to diversity? France is alone in having chosen a secular state policy. But several national and European associations support secularism and their actions have increased, particularly over the last five years. This article will analyse this evolution in Europe, using French secular policy results to examine the issues.