“An unhealthy climate grows day after day in our country,” the leaders of four major religious denominations warned in a statement over the weekend. “It’s urgent to react and get a grip on ourselves.”

But the problem doesn’t go in a single direction. It involves a dissolving and disputed notion of French identity.

As real as discrimination against Muslims has become, researchers describe the growth of Muslim communities at the edges of large French cities that are developing parallel cultures. They are said to demand an allegiance to fundamentalist Islam, thus antagonizing the national majority’s notion of the French way of life.

The result is a kind of double sense of victimization: Muslims are drawn by extremists into a rage about “Islamophobia,” while poor whites are lured toward the hard right with promises of understanding and protection by the National Front.