An expert from the European Court of Justice put a severe damper on data retention, which was put on hold in Germany, and strengthened the position of civil rights activists.
Advocate General Campos Sánchez-Bordona affirmed in his assessment of Thursday previous ECJ rulings that general and indiscriminate data retention is only allowed in the event of a serious threat to national security.
The background to the report is, among other things, a legal dispute between the Federal Network Agency and the Internet provider SpaceNet with Telekom.
The companies are resisting a requirement to store certain data for access by the authorities.
The Telecommunications Act obliges Internet providers and telephone providers to record and save data such as IP addresses and phone numbers.
However, the Federal Network Agency put the German regulation on hold in 2017 - a few days before it came into force.
Against the background of other cases, the ECJ had already ruled in October last year that data retention was fundamentally illegal.
However, exceptions are possible, for example when it comes to a specific case of a threat to national security.
The ECJ had already ruled similarly in 2016.
The opinion of Sánchez-Bordona is not binding for the ECJ judges, but they often orientate themselves on it.
A judgment on the German regulation should be made in a few months.