All cheese is not equal*.
Are you looking for hard cheese?
Because you probably will not be successful finding zero fat hard cheese in Germany.
And, if I'm really honest, this isn't a bad thing as fat carries flavour. In hard cheeses, better to use a stronger-tasting cheese (think: parmesan, 30% fat but 100% taste) but in a smaller quantity, than a weak-tasting cheese en masse.
Eating unnaturally fat-free cheese also isn't that healthy as it is a highly processed product.
There are cheeses that are naturally low in fat, one of which is
Harzer Käse. But not everyone likes it.
Other lower fat choices are those high in water such as skimmed-milk mozzarella, skimmed milk feta and feta-style cheeses, ricotta or soft spreading cheeses (Frischkäse) which can have as low as 0,2% fat.
If you really want a low fat sliced cheese,
Arla Delite has a 5% fat variety,
Aldi cheeses at around 17%,
Plus has sliced cheeses from 5%,
Lidl Linessa light cheeses.
None will however taste anywhere as good as a modest piece of Gruyère served with some dried fruit. Or shaved Grana Padano on filet steak and rocket salad with a half a lemon on the side and a swirl of decent olive oil. Or...sorry.
*actually this is not true, as I love all (real) cheeses to be honest