I draw your attention to the documentation "Die Villa
CAHN in Bonn-Plittersdorf - Ein Deutsches Haus am
Rhein" with some personal data, published by the J.P.
Bachem Verlag Koeln. A CAHN-family lived in Bonn
already before 1772 (banking-house Jonas CAHN founded)
unti WWII. Jewish cemetery: "Schwarzrheindorf"
1623-1956 (published by Michael Brocke and Dan Bondy
ISBN 3-7927-11990-0 in 1998) and a cemetery "An der
Online you find "Stadt Bonn - Municipal archives"
written in English with email-address etc.
Hanna Goldmann, Germany