This is constantly changing and has to do with:
- how many high-rise buildings were completed in the current year,
- how many skyscrapers were demolished in the current year and
- what definition one uses for a high-rise building.
Because there is no clear definition of what a tall building or skyscraper is. If you take at least 10 floors as a yardstick, Frankfurt is NOT the leading high-rise city in Germany. If you instead rely on the minimum height of 100 meters (328 feet), Frankfurt is number 1 with more than 30 high-rise buildings in Germany (according to Phorio).
Frankfurt is now considered the leading high-rise city in Germany because there are a particularly large number of tall high-rise buildings.