How should public participation take place in Chile today and, more specifically, in the post-earthquake scenario? Drawing on this question, the article describes the public participation process of the PRES [Sustainable Reconstruction Plan] for the city of Constitucion, a process that tried to reevaluate what 'participation' means and how to understand its 'public' nature. To this end, the article sets out the methodology used and some of the results obtained, but, more importantly, it examines the theoretical foundations upon which the architectural methodology of the plan was based.