Depending on the brand of the attachment points are slightly different.
-open the hood.
-under the hood take out the rivets that secure the upper part.
-around the bottom part unscrew the fasteners (you have to turn a quarter turn).
-in the wheel wells, unscrew the screws and take out the caps, release the fender liner.
-the fender liner, unscrew the screws that attach the angles to the wings.
-pulls the bumper forward from the rails in the wings (don't want to break the wires).
-remove the connectors from the equipment (if any).
-open the trunk lid.
-in the opening of the trunk, unscrew the five screws that secure the top.
-unscrew the screws and nuts that secure the lower part.
-in the wheel wells, unscrew the screws and peel the fender liner.
-for wheel arch liners unscrew one screw on each side that attach the angles to the wings.
-with the assistant gently pulls the bumper back, don't want to break the wires.
-snap together the connectors of the equipment (if any).
How to remove front and rear bumper Peugeot 806 (Fiat Ulysse, Citroën Evasion, Lancia Zeta)