Office needed for customer returns for online sales to Germany?

Question posted by Rory Baxter, on behalf of Conkca London in LA1

We're currently looking to expand our ecommerce operations into Germany. Someone mentioned to me that if you sell to Germany from the UK, you need to have a registered business address in Germany for customers to return unwanted items to, rather than the customer simply sending it back to us directly in the UK.

I've tried going through the German regs but can't see anything about this; but the person who said this has quite a bit of experience in this area so I'm not sure!

Any help would be appreciated!