The digital platform economy has been subject to various legislative interventions. In the context of taxation, the European Union has introduced obligations for digital platforms by Amending Directive to the 2011 Directive on Administrative Cooperation (2021/514) (DAC7). Despite the guidance of the Belgian legislator, certain notions remain unclear. This article focuses on the challenges related to the Belgian interpretation of the notion of “relevant activity”. It demonstrates that the broad definition of this notion gives rise to Belgian interpretations that could cause friction with the intention of the European legislator and with the fundamental rights and freedoms of the reporting platforms.