Calm down kiddies...
And, regardless of political arguments, viewpoints, economics etc, what WAS a positive thing was to see how people, hell, young people, were genuinely involved with politics, the news and the issues affect them, and were prepared to do something (whatever can be said about their methods aside) about it rather than the more apathetic society that we seem to have inherited over the recent years from our new cousins on the other side of the pond, who happily bend over for whatever the government's lobbyists decide is right for their profits.
Last decent size protests were the fox hunting and then going back to 2003, the antiwar protests, which were all seeming like a distant memory (regardless of the effect that they could, or did, have). The french seem to find something to get riled up and riot about every 6 months or so...
So, imo, well done to everyone who was there, if only for being involved and active in your life, instead of just being apathetic...