In recent years, participatory urban regeneration has undergone significant evolution in Italy, consolidating itself as a key tool for territorial transformation, both at the scale of small and medium-sized towns and metropolitan areas. This process has been characterized by the adoption of innovative approaches that encourage co-design between institutions, citizens, and local associations, alongside the shared management of public spaces. These intervention models not only promote the physical and functional redevelopment of urban spaces but also create new opportunities to strengthen a sense of belonging, improve quality of life, and support local development through greater democratic participation. This paper aims to analyze the differences between the participatory urban regeneration models adopted in small and medium-sized cities, characterized by a stronger community cohesion, and those implemented in large metropolitan areas, where complex dynamics require multilayered strategies and greater integration between traditional planning and active participation. Specifically, the paper proposes a comparative analysis of two cases of “Tactical Urbanism” at very different scales to identify differences and similarities: the “Ca.Fè.” initiative in San Nicolò a Tordino, a small town in the province of Teramo, where ten local associations collaborated to transform a former school into a multifunctional center for cultural, educational, and social activities, and the “Piazze Aperte” case in the metropolitan city of Milan, which stood out for the adoption of an integrated strategy combining various participatory approaches. The analysis, which seeks to identify the conditions that promote the scalability and replicability of participatory models, will conclude with a reflection on co-design practices and participatory approaches necessary to build more resilient and inclusive urban spaces at different territorial scales and under varying economic and social conditions.