What challenges have generations of immigrants faced in a country torn between secularism and religious diversity? As issues of immigration and integration raise Europe's political temperature, this three-part series examines the history of Muslim immigration to France - a country where debate continues to rage over how to reconcile a long-standing tradition of secularism with religious diversity. Today, there are an estimated five million Muslims living in France. A century ago, they were referred to as "colonials". During the 1960s, they were known as "immigrants". Today, they are "citizens". But how have the challenges facing each generation of immigrants changed?