This note explores the ECJ’s decision in X v. Staatssecretaris van Financiën (Case C-283/15), wherein the Court held that denying a self-employed non-resident taxpayer, who receives 60% of his income from the Netherlands, a deduction for interest expenses related to his dwelling in another Member State when that taxpayer does not receive sufficient income in that Member State to qualify for such a deduction, is contrary to the freedom of establishment.