On September 13, 2018 the State Labour Court Hamburg (docket number 2 TaBV 5/18) ruled that works councils have a right of co-determination concerning the employer’s Twitter account in accordance with Sec. 87 Para. 1 No. 6 Works Constitution Act as Twitter is a technical device designed to monitor the behaviour or performance of the employees. The respondent in this trial is an employer which operates several cinemas in Germany. It created a Twitter account and tweets on a regular basis. The applicant – the established works council at the respondent – demands that the respondent refrain from using its Twitter account as long as it does not have the works council’s approval to use it. The State Labour Court ruled that the respondent has to refrain from using its Twitter account as long as it does not have the applicant’s approval to use it since the works council has a right of co-determination concerning the respondent’s Twitter account in accordance with Sec. 87 Para. 1 No. 6 Works Constitution Act as Twitter is a technical device designed to monitor the behaviour or performance of the employees. Monitoring in this context means a process by which information about the behaviour or the performance of the employees is collected and – at least in general- recorded to make them available for later examination. In general, Sec. 87 Para. 1 No. 6 Works Constitution Act protects the employee’s general right of privacy. The employer’s Twitter account provides a platform to evaluate the employees’ behaviour and performance and it supports the employer to reach an open exchange of views with its customers. Twitter’s function called “Reply” enables any registered Twitter user to send a direct response to any of the employer’s tweets to evaluate any employee’s behaviour or performance. These replies can be seen by the employer and at least by any registered Twitter user. Depending on the content of the reply the employer can identify single employees and can use this data to evaluate this employee’s behaviour and performance. The fact that these replies are only a reaction to the employer’s tweet does not change anything since the employer does not have to intent to monitor the employees’ behaviour and performance with the provision of the technical device. Also the fact that these replies stay on the account of the repliers and cannot be deleted by the employer without the help of Twitter itself does not change anything. First, it does not matter where the actual reply is saved, it just matters who can see it. And second, the fact that the employer cannot delete the reply itself makes the interference with the employee’s general right of privacy even worse, and therefore it has to be especially protected by the works council. After the Facebook decision of the Federal Labour Court in 2016 the State Labour Court Hamburg now decided that an employer’s Twitter account also creates a right of co-determination under the Works Constitution Act. The State Labour Court’s decision has been appealed at the Federal Labour Court. It remains to be seen if the decision will be affirmed.