Real Estate / Time limitations to selling a flat in Poland (bought a year ago) [4]

Hi all,
I bought a flat in Warsaw with my Polish (now ex-)partner about a year ago. I am an EU citizen. Things didn't work out, and I'll be moving to Germany or France in a couple of months. We have co-ownership, 2/3 for me. My ex-partner doesn't earn enough to take charge of the whole mortgage. I would prefer to just sell the flat (or at least my share). But I heard that you can't sell a property too soon after buying without paying significant taxes. Is there any way to provide a "reason/excuse" for the selling? Such as moving abroad?

Thanks for any answers