Otto - no, it's not available online - you have to write to the court in question to find out about who owns what and where. It's a rather bureaucratic process I'm afraid - especially if you don't know the "property number".
Thanks a lot to Lukasz K for this real competent answer!! It really helps.....
I'm now getting closer to my target:
I'm now looking for the correct "Ksiega Wieczysta" Nr.
The notary gave me this number. But on the contract there are other numbers given like 78/4 .......
So I did try to check at:
ekw.ms.gov.pl/pdcbdkw/pdcbdkw.html
In the first box I selected SL1B (for Bytow-[the property is located near Polczno]) - in the middle box the number **664 - but what do I have to put in the last Box?
great links Lukasz.. is there a way to find who own a certain property with just parcel numbers and city/town/village location? although the cadaster map didn't really give you the exact location either..