The case started with a complaint from an unnamed businessman in Germany who claimed auto-complete linked him with "Scientology" and "Fraud."
The court has ordered Google to remove "defamatory word combinations" when told about them.
Google's auto-complete makes search string suggestions based on the frequency of searches by other Google users, and the search giant claims it has very little control over the combination of words that auto-complete might serve up. If a large group of people search a name with a keyword like "fraud" after it, then it's likely other users will see that search as an auto-complete recommendation.
A Google spokesman said the company is disappointed with the decision of the court, and said it was "incomprehensible" that Google could be seen as liable for the search content of its users.