This Qing dynasty courtyard hotel with a lovely downstairs teahouse (open to nonguests) could be the nicest boutique setting in Chongqing, but it comes with several caveats: it's somewhat hard to find, the riverside location is not convenient for getting around (lots of steps), rooms are on the small side and English is limited. It is peaceful though.
Theoretically you can book via Trip.com ('Landscape Mingqing Dynasty Inn'), but we could never get the online reservations to work – try calling instead.