Do German Buddhists have a connection with Judaism?

Some might, other's probably not. Did you imagine all of them did?

Only as much as all human beings have connections.

...although, if they follow the Tibetan Buddhism -- the Dalai Lama has done alot of "interfaith" discussions with rabbis to learn from the Jews how a nation and culture can survive protracted exile.

It is my understanding that the Tibetans under the leadership of the Dalai Lama are modeling an exilic Tibetan community on the Jewish example.

No, it's the Belgian Taoist who have, and even that connection is a bit thin.