I requested a non-smoking room with a double bed. I was given a smoking room with two twin (i.e., small) beds, and told that they were "sorry." I could pack up my stuff and have them move me to a non-smoking room the next morning--not interested in that hassle. Not only did the room and the whole smoking floor stink like cigarettes, but the shower was also pitiful: the water pressure was almost zero and the fixture to hold the shower head on the wall was broken and could not hold the shower head. And the light over the sink blinked on/off and changed in intensity constantly--very annoying. Apparently the "do not disturb" sign means nothing either, as they still entered and made up my room during the day while I had the sign displayed.
It's one thing to not have available the room choice you request, but then to just say "sorry" without any offer to make up for it, e.g., offering a free breakfast, comp a night's parking, etc., doesn't cut it. Very disappointing for a Mercure. I guess they know their clientele is somewhat hostage to their location and they just don't care about service.