When travelling to Germany and other Schengen Member States you might need a Visa.
A list of Nationals who will need a visa, and further information can be found on the website of Federal Foreign Ministry:
www.auswaertiges-amt.de/en under the section: Entry & Residence
If you already have a Visa you can find further information on our information sheet of how to read the visa sticker
With the calculator of Federal Police you can check yourself if you can re-enter the Schengen Area with your current visa.