It has been widely believed that intermediaries, and in particular online trading platforms, do not risk primary liability for trade mark infringement when a platform’s users offer counterfeit goods for sale on the platform. The role of a platform in such a situation has been considered as contributory infringement that does not incur liability as long as the platform is acting in good faith. This has now changed with the decision of the Court of Justice of the European Union in joined cases Louboutin (C-148/21) and (C-184/21), according to which a trading platform incurs such primary trade mark liability under certain conditions. This article examines the conditions under which an intermediary incurs primary trade mark liability for acts carried out by third parties.