The debate about smart cities emerged in the mid-1980s in the context of urban planning in the United States. In Brazil, due to the growing discussion about urban issues and problems, which had been gaining momentum in the national scenario since the late 1970s and early 1980s, due to the pioneering treatment given by the 1988 Federal Constitution to urban policy, phenomenon "of smart cities found in urban planning a fertile soil for proposing actions and programs by the most diverse actors, consolidating itself as a multidisciplinary area. With the rise of smart cities, the possibility of inserting the technology in the most diverse urban sectors, from the management of the city to the provision of public services, was observed. However, potential impacts of the unrestrained use of this technology, especially with respect to privacy and access to personal data, should be considered when these smart cities are to be realized. In the field of public security, the use of cameras, sensors, software of the most diverse, can compromise the information security of users / citizens. In this perspective, this study has as main objective to analyze the reach and the limits of action of the Public Power with respect to the treatment of personal data of the citizens, especially within the perspective of the intelligent and safe cities. In the end, it could be seen that the Public Power's action in the processing of personal data is justified by the principle of supremacy of the public interest over the private, in addition to the normative permission inscribed in the General Data Protection Law itself, which enables Public Administration the processing of personal data when necessary for the execution of public policies foreseen in laws and regulations. Methodologically, a theoretical-descriptive approach was used on the general themes of the research, besides the hypothetical-deductive method to answer the central problematic of the work.