Maison Albar Hotels L'Imperator
The pool. Indoor pool, advertised as heated by Staycation, with counter-current swimming, hot tub and hammam, as well as a seasonal outdoor pool (Expedia).
The hot tub. Hot tub in the spa.
I haven't yet found guest reviews that mention the water temperature.
Guide's tip. The indoor pool can be used all year; spa access can also be booked by the day.