la "cittadinanza europea" come "cittadinanza differenziata" a base di un sistema "multilivello" di diritto privato

Starting with a description of the changes in the notion of citizenship from both an historical and social viewpoint, the article focuses on the idea that this notion cannot be understood any longer in a monolithic way as identified only with nationality, namely with state citizenship, but can and should be instead articulated with reference to various socio-political as well as institutional contexts, assuming therefore various degrees of legal relevance. In this pluralistic and inclusive approach, Union citizenship can be therefore seen as a new degree of citizenship which, in addition to nationality, aims at completing state citizenship, by integrating it in the so called space of freedom, security and justice, common to all nationals of member countries; being precisely a space where nationals can act in their capacity of Union’s citizens with supplementary rights, such as those written in the Nice charter (although not having yet legal force). It then follows that Union citizenship may represent a better legal basis, than internal market, for setting in a bottom-up way a model of European private law characterised by its being complementary (additional) to national (and local) laws, thus giving rise to a complex multi-level system resembling in some respects the relationship between ius commune and iura propria of past ages.