Need help removing my headrest

C'est pas difficile, if you have the proper tool.
No need to apologize for being French; I'll bet half the posters here will spell "tonneau" wrong, or write "breaks" when they mean "brakes".

This is one of those jobs I can show you in 30 seconds, but takes 10 minnutes to explain.
The best tool I found is an ordinary heavy-duty cable tie (also called "ty-wrap" - the kind the police use for disposable handcuffs). See this page, and scroll down to part number 10038, 14.5" long, 0.251" wide, and 0.074" thick.
http://www.westernstates.net/Cable_Ties/cable_ties.html

Step by step:
Raise the headrest as far as will go (only about 1-2 inches).
Using the handle of a spoon, pry up the plastic trim piece on the top of the seatback that surrounds the metal support part of the headrest assembly. You only need to raise it enough to slide the cable tie underneath.
Work from the front of the seat, with the windshield behind you.
You will notice a groove running vertically in the center of the metal support.
Slide the lead end of the cable tie under the plastic trim piece and into the groove, bending it so you can push it down into the seatback as far as it will go (4 to 5 inches).
Now, push & pull the headrest up and down a little while continuing to push in the cable tie. You should be able to work it down another 1 inch or so.
The cable tie will now be holding in a hidden retaining clip.
Pull up on the headrest and it will come completely out, along with the cable tie.
You don't need any tools to replace the headrest; just push it back in until you hear/feel a "click".