The tariff structure for academics' salaries is very transparent in Germany. This is a good approach in light of the many different payment models in academia. It is important to note that this career will not make you rich!
Frankfurt am Main has a centuries-old tradition as a location for academia and research. In addition to Europe´s second largest airport, it has the highest concentration of banks.
The topic can make or break a dissertation. It convinces selection committees, helps earn financial support, and steers a career in the right direction.