If you are in love with authentic Art Nouveau decor, like I am, having a beer at "La Porteuse d'Eau" in Brussels is a must. You can see the part that is pictured upstairs. It looks set for large groups so I am not sure you can be sit there otherwise but you most definitely take a look. It's the typical Brussels brasserie where you can indulge with a cuisine based on beer. You will be delighted with their good beers and fabulous meals. Do try their local beer cheeses and sausages trays. You will not be disappointed.
This is why I love Belgium so much. You can find amazing things even in the most ordinary of places. I've never seen so many amazing looking cafes and restaurants like I've seen in Belgium.