[horsestaple]

True if you look at the cities, but it misses the bigger picture. There was also a trend of people moving into the surrounding suburbs and smaller towns, and commuting to the inner city. If you look at the metro area, both have actually grown.

https://www.macrotrends.net/cities/204296/berlin/population

https://www.macrotrends.net/cities/20107/vienna/population