France's unique form of secularism, known as laïcité, has historical roots in the French revolution, and values the absence of religious symbols in public spaces. This has led to tensions with minority religious groups, which also relates to the history of French colonialism and challenges around economic and cultural integration.
It's not surprising that Nigeria's 170 million people, 270 ethnic groups and over 370 languages, show astonishing diversity. This is true of its religious traditions, which include Islam, Christianity, and indigenous religions. Conflict, though often framed in religious terms, is more often a result of unequal distribution of resources than it is about belief.