While the hotel rooms are small by North American standards, it average for Europe (& large bed for Europe). The funky shower, lighting & furnature that others have mentioned give it the impression of more space. The only way to feel cramped is if you have too much luggage (after dragging too much luggage around Europe, especially up/down metro stairs, we learned from www.onebag.com how to pack for several weeks with just carryon luggage & works fine).
Only quirk with the free wireless is that you have to re-register every 6 hours - as a business traveler that would be a pain but since this is a vacation trip its OK). BTW-in room guide says no Voip or peer to peer on the WiFi, can't comment on the peer to peer but we had our Vonage Voip working fine & did a quick test of Skype with no hitches either.
€18 for breakfast is a bit steep but next door at Pomme de Pain, €6 gets a small coffee, small juice, crossent & yogurt. Room also has a very small fridge but good enough for wine, snacks, juice, milk, cerial from the Monoprix next door. Hotel can also do your laundry but there is a self service laundrymart 50m away (on rue de Monteotte) where for ~€10 can do 2 loads in under an hour.
Plentry of good resturants in the area, especially in the squares of the residential areas a couple of blocks away.
Arc du Triomphe metro station 500m away (metro 1, 2 & 6, RER A plus Les Cars AirFrance shuttle bus to/from airports) & Trenes station 200m away (metro 2), but walk everywhere anyway.
And Orange Boutique store 3 blocks down Trenes for prepaid celular phone SIM (Mobicarte) with a local #.
Great value, we prepaid well in advance for 6 nights over New Years (so still here) & got a great rate. Our last trip to Paris we stayed at a 'major' hotel (free on points), this time it was our $$$ and felt more comfortable at the Mercure. Highly recommended.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC