Postmark (Poststempel): Frankfurt am Main 1976 + slogan / Definitive stamp 1975 50pf Michel #851, Yvert #700

Addressee Postmark: Pernik C, Bulgaria

Postcard Publisher (Verlag): Michel & Co

Illustration: Riverboat "Wikinger" on Main River at Frankfurt with the cathedral in the background.

Note: The image is of the product you are going to get.
Slight wrinkle in the upper left corner.