Breyer case of the Court of Justice of the European Union: IP addresses and the personal data definition

The Breyer case of the Court of Justice of the European Union (CJEU) primarily concerns the question whether a website visitor’s dynamic IP address constitutes personal data for a website publisher, when another party (an internet access provider) can tie a name to that IP address. In essence, the Court finds that an IP address constitutes personal data for the website publisher, if that publisher has the legal means to obtain, from the visitor’s internet access provider, additional information that enables the publisher to identify that visitor. In this case note, I summarise the facts and the judgment, and add a few comments.