unfortunately France and other european countries have almost no areas open to ride motorbikes (dirt bike parks or race tracks, etc) so the kids can only go mad on the streets.. Having access to dirt bike parks would probably alleviate the issue, but the governments don't want to put land aside for that, (they don't want motorcycles destroying the countryside and making noise!!) so the only thing left is to clamp down on everyone behaving dangerously on the street. Address the symptoms not the cause.