Johannes Caspar, head of the Hamburg Data Protection Authority, sent Facebook a letter, in which he argued that facial recognition amounts to unauthorized data collection on individuals. Caspar sent the letter on Wednesday, and has given Facebook two weeks to respond.

This is far from the first time Facebook's --the feature , and it's been . Pushback against the feature increased in June after that the site had expanded its use of the facial recognition feature. This prompted for how it had handled the rollout.

The European Union's advisory board--the Article 29 Working Party--is also looking into Facebook's facial recognition and whether it's a violation of EU law. Investigations at the member-state level are underway in Ireland, the United Kingdom, and, now, Germany.

If the social networking site is found guilty of breaching consumer privacy, German laws allow Facebook to be fined up to 300,000 euros ($429,000). Regulators would also be able to force Facebook to disable facial recognition within the country.

Facebook has defended itself by denying that it's doing anything wrong--though the company did say it would take Caspar's concerns into consideration. "We will consider the points the Hamburg Data Protection Authority have made about the 'photo tag suggest' feature, but firmly reject any claim that we are not meeting our obligations under European Union data protection law," a company spokesperson said.