Compliance Officer in financial sector in Luxembourg here.
The request you have received is related to anti money laundering regulations. As you guys seem to be based in Germany. So bear in mind that PayPal operates across the European Union as a Luxembourg-based bank. Anti-money laundering regulation is typically stricter in Lux than in the USA. The Lux regulator is the "CSSF", and you can find the detail of the regulation here: http://www.cssf.lu/en/supervision/financial-crime/aml-ctf/la...