This paper analyses the legislative technique adopted in the DSA to refer to fundamental rights in defining the obligations of private entities. First, it introduces the horizontalising effect of fundamental rights brought about by these new obligations, drawing a comparison with other EU legislative initiatives. Second, it looks at two questions raised by the horizontalisation of fundamental rights in the DSA, i.e. what elements should guide the balancing between fundamental rights and the other interests at stake in this context, and how far should the obligations of online intermediaries go. By answering these two questions, this paper concludes on the factors that should be taken into account in understanding the horizontalisation of fundamental rights under the DSA, and how they could guide the interpretation of the relevant obligations for online intermediaries.