The paper examines the principle of equality as it is traditionally interpreted and applied in EU tax law, with the aim to understand to what extent it is necessary to reconceptualize it after the Lisbon Treaty and the introduction of the EU Charter, which makes fundamental and human rights and sustainable development binding principles for the Union. EU law is built on the principle of equality and on an interpretation of it that has economic origins relating it to the concept of formal equality, firmly tied to the creation of the Common Market in 1957 and to the European Economic Community (EEC) as a community of trade based on the four fundamental freedoms. EU governance in matters of taxation as originally framed in the Treaty of Rome was informed by this view, and led to a EU tax law framework aimed at ensuring equality in terms of competition on the one hand, and economic freedoms on the other. This modus operandi has resulted in an EU tax law system that only implements the conceptof formal equality, and which casts tax payers solely as “homines oeconomici”, “agents of the production system”. This is as certainable, for example, in the line of reasoning followed bythe Court of Justice of the European Union (CJEU) in their judicial review of whether the tax systems and the tax regulations of Member States were to be considered a restriction to the exercise of the European economic freedoms, and whether national regimes discriminate against cross-border activities when compared to domestic ones.
The introduction of binding concerns for fundamental and human rights and for sustainability as part of the EU legal framework implies the addition of a second, substantive dimension to the conceptualization of the right of equality which necessarily poses the issue of reassessing the meaning and bearing of the concept itself. This paper investigates two of the grounding questions for a reassessment: how the principle of equality should be reconceptualized to account for its substantive dimension as required by the Lisbon Treaty and how said reconceptualization would affect the very foundations of the power to tax in the Union.