German data privacy authorities have re-opened a probe into Facebook and its use of biometric facial recognition to determine whether the company is violating privacy protection laws in Europe, according to an article from BiometricUpdate.com.

In June 2011, Hamburg’s office for data protection and freedom of information suspended an investigation into Facebook’s use of facial recognition technology, to give the social media company to change its policies, the article says. Data protection commissioner Johannes Casper stated at the time that he believed that Facebook had been illegally collating face recognition data about its members without explicit permission, in order to populate the photo tag suggestion feature.

Casper says that he re-opened the investigation “in order to find a legally sound solution with regard to the use of biometric data,” the article says. The office is critical of the fact that Facebook automatically opts its users into the photo tag feature, but it acknowledges that the site allows its members to opt out again.

In Europe, however, data protection laws require users to give their explicit consent.

If Facebook is found in contradiction of German law, the company could be fined or ordered to make changes to its service, the article says. This could potentially be a major setback in Facebook’s plans to make integration of biometrics a major component of its service, especially after its June acquisition of Face.com.

According to the article, Facebook said in a statement published in the New York Times that it believes it is in full compliance with the law. “We believe that the Photo Tag Suggest feature on Facebook is fully compliant with EU data protection laws. During our continuous dialogue with our supervisory authority in Europe, the Office of the Irish Data Protection Commissioner, we agreed to develop a best practice solution to notify people on Facebook about Photo Tag Suggest.”