The ruling said Facebook should have to get permission separately before using customer data from other apps and websites to do so.
Facebook is pushing back against a German ruling that could make it harder for the company to combine data from all the services it runs in order to target ads even more precisely.
Thursday's ruling, though aimed at current practices, hints at potential troubles ahead if Facebook follows through with plans to integrate the messaging functions of WhatsApp, Instagram and Messenger as early as next year.
