Perhaps part of the problem in France is having essentially zero minority representation in government? I don't know the statistics.
Regardless of what you think about American policies, we do have a pretty good record of finding minorities to fill important positions. For example, one does not need to look very hard to notice the highest ranking cabinet post, and fourth in line to be "the most powerful person in the world," is a black woman. And there are obviously a number of Hispanics in government. Ralph Nader, an important (although never elected!) politician, had Lebanese parents.
It seems to me that rioting is sort of a last ditch attempt to make a statement, and the lack of recent violence in America may reflect the availability of other methods to voice one's opinion.
