In Belgium, the rules come as a regular surprise to a lot of married Englishwomen coming over here and settling for long enough to register with the authorities - having become used to using their husband's family name (I don't say "surname" since we are talking about Belgium - in French, "surname" ("surnom") means "nickname") they find that this doesn't work here - all official documentaion, signatures, etc for a married woman must use her maiden name!

Edited for spelling.