The principle of openness, mentioned in the first article of the Treaty on the European Union acts as a foundation of a global research into the interaction between taking decisions and the citizens of Europe. This approach is motivated by a willingness to improve the legitimacy of European policy. However, it should be distinguished from the democratic principal of law within the Union, in that it does not attempt to reinforce the status of European citizens within the European political regime, but attempts only to offer them possibilities of influencing the core of such decisions. The possibilities of influence are constantly looked at in depth, through reorganizing such principles as transparency and participation, and by the installation of mechanisms of dialogue through consultation, the right to petitions, the right to use a mediator or even create citizens initiatives. The study tries to measure the degree of influence that European citizens have on decision making, and to compare them to the objectives of the principle of openness