It's set at a city/regional level in all of Germany, there are just very few areas that offer very low taxes. Those tend to be close to large cities to get companies to move headquarters out of the city. Hamburg and Frankfurt also have areas with one of the lowest tax rates just outside of city limits (not sure if Munich has one).
In the end, I'm not sure if it makes such a big difference, other incentives, land prices and availability of talent probably outweighs this.
