Easily Warsaw, all 5* properties go for well below € 100 on weekends and not much more during the week, even suites are available in the € 150 range.
Westin, Interconti and Hyatt Regency are brand new...
Berlin is (in)famous for the low yield in the hotel business, at year´s end Berlin will have more than 30 5* properties.
FS already pulled out of the market, cause there is no money to be earned...