Kosher meat is Halāl as it fulfils the requirements
of Islam which are basically two:
1. Allah’s name should be taken on the slaughtered animal
2. It should be slaughtered through the jugular vein so
that all the blood is poured out.
Eating meat from fast food restaurants should only be done
in case it is known that these restaurants sell Halāl food, otherwise they
should be avoided. In Pakistan, they serve Halāl meat. I am not certain for
Germany. You can find out about the meat used there yourself.