A lot of people left West Berlin when the city was divided and a lot of people left East Berlin right after reunification. The massive housing surplus that resulted caused housing costs to sink and cheap housing made the city a mecca for alternative culture. Cost of living probably doesn't even hit a quarter of Paris or London.

Here's an article from 6 years ago that's somewhat dated, but still gives you a feel for things good and bad:

http://www.businessweek.com/magazine/content/02_23/b3786132....