Earlier quoted context omitted.
A flat that cost 500-600K in Berlin would be rented out at 1000€ a month, that can’t increase more than the rent control allows. A mortgage would cost 3 times as much. So you’d be better off renting and investing the deposit, the stamp duty, notary costs and the 2000€ you save each month in government bonds.
Are you sure about these numbers? As ROI doesn't make any sense to me in context of the new investments built solely for rent. How does it work?
https://www.numbeo.com/property-investment/rankings.jsp
The ROI absolutely does not make sense but it's real. A large portion of the world believe that the only two investment classes are real estate and government bonds.