In this article, the authors discuss triangular situations similar to Saint-Gobain. The focus is on the interaction between double tax convention law and EC law. The position of the permanent establishment state, the residence state, and the source state will be studied. Central in this article Company X established in state R with a PE situated in state P that acts as a ‘recipient’ of passive income paid by company Y from state S. The authors conclude that, in the first place, state R has been designated to prevent double taxation by means of an exemption or a credit. Secondly, if state R uses the exemption method, the responsibility switches over to state P and state S together. Not only must state P (as a Member State) treat a PE as a resident for treaty application, but also state S (as a Member State) has this obligation if a remaining juridical double taxation is caused by neither state R nor state P. This conclusion is not negatively affected by Damseaux. Thirdly, if state R uses the credit method both for PE profits and for passive income, it is obliged to apply the credit method in accordance with both the R-P Double Tax Convention (DTC) and the R-S DTC. Then, there is no European obligation for state S to mitigate the source state taxation.