If users aren’t warned that their private information is being shared Facebook ‘like’ buttons on commercial sites break German law, a court ruled on Wednesday.

The opinion came in the issue of a shopping web site using the Facebook Like button on its web site. It has been prohibited by the court prohibited if it didn’t warn customers their information was being recorded from using the Like function on its pages.

On the other hand, the opinion may have a far reaching impact in route sites running in Germany incorporate Facebook Likes. “A simple link at the foot of the web site to a data protection statement doesn’t represent an indicator that information are being or are about to be processed,” the court said. The opinion may have consequences in other European nations too.

Trend ID was taken to court by consumer organization Verbraucherzentrale who accused of failing to conform to Germany’s data protection laws the website.

A Facebook spokesman reacted to Wednesday’s opinion, “This case is unique to a special site and the manner they’ve sought permission from their users before. The ‘Like’ button, like many other attributes that are used to improve sites, is a significant, legal and approved part of the Internet, and this opinion doesn’t alter that.”