I made a mistake, usually I don't take any breakfast and I did the reservation without it. Once at the hotel I have been asked if I wanted it and I accepted it. By the end of the stay I didn't use it the breakfast at all, and correctly they felt like charging it, but by the end they understood my situation and they have been kind enough, not to charge me. This by the time I did the reservation without and as I haven't used it.
However, the réceptionist has been pushy and strong on her point. Only when I accepted to pay it for not having more troubles, she stepped back and decided not to charge me. The situation was a bit unexpected and ruined a bit my great opinion at the real end. Either you charge it or you don't charge it it's fine to me, but don't create a théâtre in the réception.
For everything else, rooms are clean, a bit dark, very nice bathrooms, great location and you are in Montreux in 10-15 minutes either by train or by bus.
Thank you for everything!