Tour de France--is there any law regulating spectators?

There was a thread in the Pit yesterday titled “long live Lance–but those idiotic spectators…”---------which got me thinking:

Is there any law in France that governs the spectators?

Millions of people line the route, and tens of thousands of them stand right on the asphalt, and/or in front of the riders. Often, they are waving flags on long poles. And occassionally, it causes a crash–but only very rarely. Maybe once or twice during the 3 weeks, despite there being thousands of near misses.

And if some crackpot hates a certain lead rider, it would be easy to block him, or worse.
Does French law have anything to say in such a case?
Or what about the regulations of the sports organizations? Anything comparable to , say, penalties imposed on a team due to football (=soccer) hooliganism?