@ Trumpy
France has got different types of polices:
As far as I know the guys that were on the police side in this case, are part of CRS, which is unfortunately known as a sort of bloodhound gang. Nobody whether French or immigrant or even a regular "gendarme", really likes them and they usually just get the dirty jobs. So when you meet them and they are stronger as in this case, it is not for sure that you will be treated correctly.
On the other hand you got in France a lot of urban youngsters that really have no home and no real chance. Difficult to blame one party for that. Just the kids are often still kids not knowing what they do.
This means, as far as I can judge the situation, that there effectively exists a certain liability on the political side.
The rest is a lot of mass media hystery and ist effects.