The regulatory vector for satellites in the US is the FCC. The FCC controls US airwaves so if you're providing services via satellite in the US you must have a license from the FCC.
So if you're a non-US company operating services in the US, you'll have to have a US subsidiary anyway and that subsidiary would be required to get the license. If you're a non-US company not doing business in the US then that's outside of regulatory jurisdiction.
By the outer space treaty, ultimately it's the responsibility of the country that the company belongs to. If it was a german operator, it'd be subject to German rules.
Although of course since this is geostationary orbit, the point of putting it over a geographical area is to do business over that area down on Earth.
So, if it was a German company, but was doing business in the US, the US could use access to their market as leverage for a fine.
The geostationary satellites I’m familiar with fly directly over the Equator, no point on the Equator is in Germany. The disposal orbits are geosynchronous and have a more interesting ground track. I think their ground tracks are still equatorial countries.
Geostationary satellites have antennae which are meant to optimize communications with ground stations in certain countries, but they can’t fly over the USA especially.
In that case presumably the other country would be responsible for issuing a penalty, assuming symmetry in a fair world (which is a fairly questionable assumption).
So if you're a non-US company operating services in the US, you'll have to have a US subsidiary anyway and that subsidiary would be required to get the license. If you're a non-US company not doing business in the US then that's outside of regulatory jurisdiction.