Of course incitement to riot should be prohibited. This is the “imminent lawless action” test of Brandenburg v Ohio.
http://en.wikipedia.org/wiki/Brandenburg_v._Ohio
But what France proposes to do is ban ALL Muslim demonstrations. This is not a road we here in the United States should head down.
The government just needs to show the connection between Muslim protests and the inevitable breech of peace. Like this:
http://www.google.com/#hl=en&sclient=psy-ab&q=muslim+protests+turn+violent&oq=muslim+protests+turn+violent&gs_l=serp.3...7299.11150.0.11322.14.14.0.0.0.0.195.1748.1j13.14.0.les%3B..0.0...1c.1.ghypLQwbnEk&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=8f6a380074f83e6a&biw=1440&bih=712