Do I need a visa to be an Au Pair in Germany?

The short answer to this is - it depends. People who hold European Union/EEA or Swiss passports do not need a visa to become au pairs in Germany. People from other countries will need to apply for an Au Pair visa to come to Germany. You also need to prove basic language skills in German in order to apply for an Au Pair visa. For that an A1 level language certificate, recognized by the Goethe Institute, is required. Here is a full list of German visa options by Expatica.