Under the heading of the “2030: Digital Decade”, strengthening people’s awareness on the CFREU – as well as empowering civil society organisations, justice practitioners and academic communities – is an imperative for survival of democracy and rule of law in the EU. But who in fact are the addressees of the provisions of the CFREU? Article 51(1) CFREU highlights the vertical effect of its norms – that is, their relevance to relations between the authorities exercising public power and individuals or legal persons –, apparently excluding their applicability to relations between individuals or legal persons. It is true that the horizontal effect of fundamental rights is not accepted in the vast majority of Member States’ Constitutions – even though, through the infra-constitutional regulation of private relations between individuals, fundamental rights eventually have horizontal effect in some areas. Why the horizontal effect of the EU fundamental rights is so relevant to the digital citizenship? Because today private actors, such as online platforms, define their own terms and business models, assuming functions that are intrinsically connected to the exercise of public power – but without the desirable transparency, accountability, explainability and reasonableness of processes and decisions. It is indispensable to ensure that the exercise of power, particularly by private entities which dominate the digital environment, is limited by an adequate framework of legal norms. The value of the rule of law (Article 2 TUE) underlies the defence of citizens against any power, submitting power to the law. This challenges EU to join constitutional forces and to make the digital decade an opportunity for the fundamental rights protection in a Union based on the rule of law. In this context, sustainability is shaped as a matrix concept of the digital decade, defining the conditions and the assumptions for legal regulation in a context of permanent technological evolution.