Why?

From an RFE/RL report on the violence in Paris:

Witnesses say attackers repeatedly hurled homemade fire bombs at one sports gym in suburban Paris from the top of a nearby residential building -- fueling the blaze even as firefighters tried to extinguish it.

A woman who lives in that neighborhood called the destruction a senseless act of hooliganism: "It is something horrible. We don't understand. We are in shock. When we see something like this, we are completely beside ourselves with anger about such senselessness. It is true that this gymnasium was a golden opportunity for all the youths [in this neighborhood] -- and for all the people who were using it. It had very modern facilities. So we just don't understand."

And from the New York Times:

Many politicians have warned that the unrest may be coalescing into an organized movement, citing Internet chatter that is urging other poor neighborhoods across France to join in. But no one has emerged to take the lead like Daniel Cohn-Bendit, known as Danny the Red, did during the violent student protests that rocked the French capital in 1968.

Though a majority of the youths committing the acts are Muslim, and of African or North African origin, the mayhem has yet to take on any ideological or religious overtones. Youths in the neighborhoods say second-generation Portuguese immigrants and even some children of native French have taken part.

In an effort to stop the attacks and distance them from Islam, France's most influential Islamic group issued a religious edict, or fatwa, condemning the violence. "It is formally forbidden for any Muslim seeking divine grace and satisfaction to participate in any action that blindly hits private or public property or could constitute an attack on someone's life," the fatwa said, citing the Koran and the teachings of Muhammad.