All rights reservedSilva, Paulo2023-12-072023-12-072015978-80-01-05782-7https://hdl.handle.net/20.500.14235/1082Book of proceedings: Annual AESOP Congress, Definite Space – Fuzzy Responsibility, Prague, 13-16th July, 2015Informal settlements rose in the developed world for some decades, affecting, in the European context, mainly the southern countries. Many have been the models to react to this dynamic, namely through legal action. In todays' world this is still affecting a significant part of the population, according to main world institutions (UN Habitat, OECD, World Bank). It is estimated that in Europe there are still around 50 million people live under these conditions. In the past, Portugal was one of the countries most affected by informal settlements. In the 1980's over one tenth of Lisbon's population was living in slums and in illegal urban areas. What started by being a critical issue in territorial terms is today almost an inexistent problem. This paper will focus on the way planning institutions were able to design a responsive legal framework, addressing informal settlements and creating a setting favourable to regenerate those areas. The paper will discuss the role of planning institutions, as well as the role of informal settlement in the law making process and in the law improvement process, a process that started in 1995 and lasts until nowadays. Beyond the formal procedures there were some key factors which warranted the success of this tools: several decades of experimentation, short links and a constant interaction between agents will be presented.EnglishopenAccessconferenceObject729-737