The hotel displays a 4 stars at the entrance.
Nevertheless, no fridge with beverages, no electric kettle with tea and coffee and no iron in the room.
Moreover, i needed a basic information about the city (about car parking at downtown) and the answer was absolutely wrong :-(
Except these points, hotel is clean, calm, with good Wifi/Internet access from inside the room, beds are comfortable.
Notice that despite its name ("Mercure Stuttgart City Center") it is located 2 kilometers away from downtown (Stadtmitte) and there is just nearly nothing (kind of human desert) during all the week-end) between the hotel and the real center of the city (Stadtmitte) where the shops, the restaurants, the bars, etc, are.