You can also connect to geni.com
Geni is a Genealogy Website.
It does not list phonenumbers like historic Whitepages
but date of individual people from Germany
and their relatives.
In case you do not find the person you are looking for
you might find some relatives that could help you.
You can "walk a family tree" from one end to the other.
Geni was founded in 2007 in Los Angeles.
Since 2012 the company is owned by My Heritage based in Israel.