To the poster who said there are no local French police, you are mistaken. Police Municipale can always be seen on the roads.
My mistake and thank you for correcting. I have never noticed anything other than the Gendarmes. If there are local police, they should be taking the lead in dealing with protestors. I saw lots of heavily armed Gendarmes in riot gear standing around in Marigot on Friday, and a few in Grand Case, but no other police.