Acting as an EU member, Romania participates in the legislative process at this level and recognizes the direct applicability, immediate and priority applicability of EU legislation in national legal framework. Even if specialized legal literature has presented consistently the principle of fiscal sovereignty of member states within the European Union, we should note the need for tax harmonization and the progress that has already been made in this direction. Tax harmonization at EU level is the complex process of aligning the normative rules in taxes levied by the Member States in order to reduce (and, if possible, eliminate) the negative effects the differences between Member States tax systems are generatingon the common market. The most effective instrument for implementing tax harmonization is, in our view, achieving a Fiscal Union among the Member States. Inside the EU, the level of tax harmonization is far outweighed by the monetary harmonization, despite the fact that fiscal policy and monetary policy should be closely linked. This lack of coordination was even more evident throughout the global financial crisis that hit European Union states. In this framework, Member States have negotiated and signed the Fiscal Treaty, a legal tool that provides mandatory measures on the supervision and control towards financial and fiscal stability. In our opinion, the solution to macro-economic stability of the Union could be to regulate a single European tax. In Romania, the legal system is beneficiary of a effervescent tax regulation and continuous reform for alignment with EU harmonization stage in the field. Both the reform and fiscal integration arestate priority. The new Romanian Fiscal Code respond to three present demands: it provides legislative support for the government's fiscal policy, it transfers into practice the rule of harmonized law at EU level and it equally pays respectto the still recognized sovereignty of Member States.