I have the following situation: I'm travelling next week with my children from Chicago-via Berlin- to Sofia (Bulgaria). We all have dual citizenship and both passports- US and Bulgarian. My US passport and my son's too expire Sept 18, 2015. Our Bulgarian passports are ok. We are planning a return from Sofia-via Berlin- to Chicago on Aug 12. I was told by my agent to check about the NEW VALIDITY rule of Germany. Can someone help? My logic tells me that we will make it to Bulgaria, but on the way back will the German authorities let us come back to the US?
As a Bulgarian passport holder, you are an EU citizen. Germany cannot prevent you from entering Germany on the basis of your citizenship. You should have no problem returning to the US through Berlin.
At check-in on your return trip, the airline will check your US passport to ensure that you have the right to enter the US in Chicago.
When passing through exit passport control in Berlin, be sure to use the same passport that you used to enter Berlin. This will probably be your Bulgarian passport, as the Schengen visa rules require that visitors have a passport valid for 3 months after the planned date of departure, and your US passports do not meet that requirement.