A German privacy watchdog has said Facebook is barred from enforcing its controversial real name policy.

The Hamburg Data Protection Authority was responsible for the decision, stating that Facebook’s real name policy violates privacy rights.

The watchdog polices Facebook in Germany, and said the social network cannot change users’ selected usernames to their real names.

According to the authority, it is not within the American company’s rights to ask for official ID to allow access.

The policy has been criticised by many around the world, particularly for issues caused for transgender individuals, and some drag artists.

One woman’s complaint to the watchdog led to this decision – she had been blocked from her account for using a pseudonym and told to provide ID.

She did not want to use her real name, as she did not want to be contacted in relation to business issues.

A spokesman for Facebook said the company was disappointed, and that the policy had been deemed in line with EU law on several occasions in Germany.

“The use of authentic names on Facebook protects people’s privacy and safety by ensuring people know who they’re sharing and connecting with,” said a spokesperson for the company.

The German authority is also working with a Belgian privacy watchdog, as well as their Spanish, Dutch and French counterparts to look into the lawfulness of the policy.

Since the company’s European headquarters are based in Ireland, Facebook says it should only have to abide by Irish law across Europe.

In 2011, Ireland’s privacy watchdog deemed the real name policy legal, citing child safety, and online harassment.

But this week, Johannes Caspar, the Hamburg Commissioner for Data Protection, said that was not the case, and rejected the argument about Irish law.

He told Reuters: “For that matter Facebook cannot again argue that only Irish Data Protection law would be applicable … anyone who stands on our pitch also has to play our game.”