Urban planning has seen a significant paradigm shift in recent years. From a public function limited to the regulation of building volumes, it has become an overall “territorial management”, in which local communities have assumed a new centrality. This has led to the need for decision-making processes to be guided by the concerned population, in order to direct public authorities in a self-represented development direction. A requirement that clashes with a legal system that considers public participation exclusively in the form of ex post observations about already taken decisions. This gave the opportunity to experiment new spontaneous forms of participation, which in some cases have found acceptance in urban planning laws. Participation has thus become an ex ante constraint for the public decision maker. The contribution aims to make a survey of the most interesting experiments that can be identified in the European legal area, in order to draw useful “de jure condendo” hints.