Perhaps one way to ease the pain a little is to imagine how much the same room will cost
post renovation!!

Perhaps the Hilton Arc de Triomphe nearby may have been a better alternative? But for 300 Euro in Paris it is virtually impossible to get into any true palace hotel -- I think the lowest is about 500 Euro at the Plaza Athenee and as high as 650 at the Four Seasons in which case the Royal Monceau is priced accordingly. However, thanks for the warning of the hotel.