That just feels like the kind of stunt a totally incompetent DIYer with much more self-confidence than skills and knowledge would pull! I once had the dubious pleasure of viewing an 1840s flat in Vienna that was wired in a somewhat similar fashion, perhaps by the poor sods who rented it without any sort of heat (didn't see any evidence of active chimneys, definitely no central heating whatsoever). We're talking 80 sq. m. (so something over 800 sq. ft.) and the incoming mains was 1.5 mm2, no earth! If there was any earthed wiring at all (I seem to remember there was, although the place had been partly gutted with barely any sockets and switches remaining) it had been connected to the water pipes - legal up until 2001 but this story took place in 2014 I think. The supply had been disconnected and the Neozed main fuse showed no trace of key rings but from the scorch marks the supply wires left above the surface-mounted consumer unit I'd suspect at least 25 A. The loo was wired with loose 0.75 mm2 flex and pattress boxes dangling on the flex, everything else was at least inside the walls.
On top of that the whole place was damp, the floor boards rotted and all the windows looked right onto the pavement - ground floor, facing north too, so it was glum. Needless to say the friend who was originally interested didn't take it. I strongly suspect before trying to sell it off at a huge profit a greedy landlord rented the place to poor immigrants with little knowledge of Austrian laws at a vastly inflated rate (there's a pretty tight limit on rents for places like this, while you can for example legally rent out living space without any plumbing, the maximum rent is close to non-existent).
