Missing real estate bubble start

One of the reasons I decided to move to Munich 9 years ago, when I had choice of Paris, London and Munich was there was no housing bubble. I missed buying a flat here at decent prices because of many reasons I don't want to go into here. Now the affordability approaches records set by Sydney and Hongkong, so I decided not to bother.

but..

Today I found a very interesting offer - a flat located very close to center of Munich (at a center of my favorite neighborhood, close to all amenities), everything perfect, ~50% !!! discount at a market price! Drawback - the house is big and 90% of inhabitants are receiving social benefits, many immigrants (but as an immigrant myself I don't mind at all).

I thought the discount in this case should have been 10-20%, so I am probably missing another important factor. What else could it be?