Frankfurt state court spokesman Arne Hasse said the ruling banning the UberPop service from offering rides with drivers who don't have taxi permits was issued but it can be appealed.
The ruling stems from a suit brought against Uber by a German taxi association, which was heard in Frankfurt because it is one of several German cities where Uber launched operations.
The court issued an injunction banning Uber from operating last summer but lifted it a few weeks later, saying that while it considered Uber's practices illegal an emergency injunction wasn't justified.