In the UK zip-codes are house (and appartment) specific. Thus a letter posted to 'GB- DL3 7TU' (the GB is not needed if somethig is posted in the UK) will be delivered to my mother's apartment.
In France, postcodes are for entire villages or towns. Thus 11130 represents all of 'my' village, Sigean.
I recently auto-mailed myself an envelope addressed to 'Herman, 11130'. It was safely delivered to me, possibly because I'm the only Herman in the village. And also because the local post office knows by now that I send and receive weird, wonderful and unusual items of mail....not all, I beg to assure you, to myself!
Regards, JE Sweefoo
I am going to try sending something to you now Ruud at that address just for the hell of it.
The mail sorting computers in Toronto have a hell of a time with mail art. It always seems to be returning about 10% to my home address despite hiding it, writing it upside down or other attempts at subterfusion.