It looks like a door, but it is no door. I believe more things should have this type of sign on them.
This sign is also useful for its Rosetta stone property of telling you how to say "this is no door" in Flemish, English and French.
The restaurant that has this sign, an excellent place for bread and soup, is where I learned the following useful bits of Flemish:
- boterhammen - sandwich
- kip - chicken
- koffie verkeerd - coffee with milk
- cheese - kaas
- spek of hesp - bacon or ham
You can also pick up some useful bits of Flemish by watching English shows that are subtitled on the hotel room TV. Manon and I both made a point of memorizing "Dat was vreemt" ("that was weird") while watching a pair of Australian guys interview a lame-o Belgian magician.