I have a 2012 Fusion SEL with the Monochrome appearance package. I removed mine from under the car by dropping the plastic panel that protects from underneath and part of the inner wheel well. The fog lamp and black inner assembly actually attach to the chrome surround which is then attached to the car so when the chrome part is free the fog lamp comes out with it. On my parts there are 4 molded tab clips on the back of the chrome surround that fit into slots on the car. Once you remove the underside panel, 3 are visible or easily to backed out. There is 1 on the top side which was a little hard to remove as you can't see it from underneath but you can access it. You kinda have to feel your way on that one. Once you see the lower clips you'll be able feel the upper one and free the assembly from the car. I used a very short, broad screwdriver to pry the clips free. There may be an easier way but....this worked for me and didn't take too much time. Everything went back together cleanly.
I replaced the chrome surround with the SE black version. Looks much better in my opinion.