AVOID monaco. never go there. the whole shtick is tired, and the hotel de paris is about as glamorous as a traffic light.
i had a decent dinner at loius xv. most dishes would have been superb eaten somewhere else ... but the choice of wines was really shocking (one of our guests wished to leave it to the sommelier, who dumped onto me some awful '93 meursault) and the setting had as much conviviality as a mausoleum - it really felt wrong to eat such simply elegant food in such an over the top lavish setting.
on the other hand, the chateau saint martin ... but thats another post.