Season the chicken with fleur de sel and using a brush or your hands, spread mustard all over the chicken skin. Stuff the chicken with the lemon, shallot, thyme and rosemary.
Place the potato wedges at the bottom of a large roasting tray. Pour the whole olive jar of olives and oil on the potatoes. Add the dried oregano, lemon slices and garlic head.
Place the chicken on top of the potatoes and olive branches (if you have) and drizzle with olive oil. Place in an oven preheated at 450 F for 15 minutes or until you get a nice coloration and turn the oven to 350 F for 30 minutes or until you reach 165 F internal.