It's perfectly in line with existing German Data Regulations (although they get a minor update too with the DSGVO coming along with the GDPR). Data retention laws in Germany supersede the GDPR. The GDPR itself also mentions that any regulation and law in your jurisdiction may supersede anything in it.
Even that data isn't owned by you. You are merely responsible for keeping it safe while you have to store it. Ultimately it's the customers data. End of story.
Which is entirely silly and basically contrary to everything else, e.g. data retention regulations that assume the company owns the data.