Here's what Wikipedia, (I know, I know), has to say about Islam in Marseille.
Marseille is France’s second-largest city with a population of 850,000 in 2010. It is also the fourth-largest port in Europe.
As official data on religion are generally not collected in France on the principle of secularism ("laïcité"), the precise number of Muslims in Marseille is not available. However, recent research suggests that about one third of the population is Muslim which makes Islam Marseille's largest and most significant minority religion.
Demographers suggest Marseille will be the first Muslim-majority city in Western Europe.
Nature abhors a vacuum. Once France rejected Christianity as the moral and legal foundation, it was only a matter of time before moslems filled that vacuum.
Listen up USA!