My father was born in France, but both of his parents ( my grandparents) are German. I was born in the US... am I eligible for a German Passport??

German passports are only issued to German citizens. You are a citizen of the United States. Your Father was born in France, where was your Mother born? You might stand a chance of obtaining a German passport if you could prove your parents were both German citizens at the time of your birth. Were they? What about your Grandparents?

You should contact the German embassy and ask if the rule of 1975 still applies to obtaining a German passport. See the following post. Perhaps that will help you.

https://www.askmehelpdesk.com/search.php?searchid=2033703

Federal Foreign OfficeSearch results (http://www.auswaertiges-amt.de/diplo/en/suche/Suchergebnis.jsp)