Clemensch
Since no one from Germany has responded to your initial enquiry, the best person to ask is your local post office. With 50 pieces of banknotes, it may make the mail a bit bulky and as such they may ask you the contents of the mail. Printed matters are always my answer, or personal documents. You might want to ask your beneficiary how it is in India. Presumably, you will be posting the notes via registered mail. 😁
Good luck.
