European cities can be conceived as forming a system of well interconnected cities since many centuries. The peculiarities of their hierarchical functional organization and territorial patterns have been the subject of numerous analyzes. The purpose of this paper is to detail a few contributions from the science of complex systems to formalize this knowledge. This includes representing the metropolization process occurring within a system of cities with the help of scaling laws and network analysis. We define here the metropolization process, not at the local level of one metropolitan area, but at a macro-geographical level, as the ability of larger cities to capture at first the activities related to innovation waves and being the first to benefit from them in terms of population growth. A series of relevant urban attributes are used for quantifying through scaling laws exponents the differentiated behavior of urban hierarchies when opening to the global networks that characterize the most recent wave of innovation. Network analysis brings another type of formalism that helps constructing a better understanding of how the globalization processes, especially described with the spread of multinational firms, have diffused in the Eastern part of the European urban system.