The problem for a terrorist group like al-Qaeda is that its recruitment pool is Muslims, but most Muslims are not interested in terrorism. Most Muslims are not even interested in politics, much less political Islam. France is a country of 66 million, of which about 5 million is of Muslim heritage. But in polling, only a third, less than 2 million, say that they are interested in religion. French Muslims may be the most secular Muslim-heritage population in the world (ex-Soviet ethnic Muslims often also have low rates of belief and observance). Many Muslim immigrants in the post-war period to France came as laborers and were not literate people, and their grandchildren are rather distant from Middle Eastern fundamentalism, pursuing urban cosmopolitan culture such as rap and rai. In Paris, where Muslims tend to be better educated and more religious, the vast majority reject violence and say they are loyal to France.
Al-Qaeda wants to mentally colonize French Muslims, but faces a wall of disinterest. But if it can get non-Muslim French to be beastly to ethnic Muslims on the grounds that they are Muslims, it can start creating a common political identity around grievance against discrimination.