A cidade sob vigilância: limitação proporcional da privacidade como instrumento de proteção coletiva nas cidades inteligentes

Abstract

The incorporation of facial recognition technologies and algorithmic monitoring into public security policies has profoundly reshaped urban space within so-called smart cities. The expansion of these tools, driven by promises of efficiency and crime prevention, significantly enhances the State’s surveillance capacity while intensifying constitutional tensions concerning privacy and personal data protection. Contemporary debates frequently polarize between the absolute rejection of such technologies and their unrestricted adoption under claims of operational effectiveness. This dissertation seeks to move beyond this dichotomy, arguing that the central issue lies not in the technology itself, but in the normative and institutional conditions that structure its use. The research problem consists in determining to what extent the limitation of privacy, within the context of smart cities, may be legally conceived as an instrument of collective protection without compromising the essential core of fundamental rights. The hypothesis advanced maintains that the proportional restriction of privacy, when guided by a constitutionally legitimate purpose—particularly public security—and subject to structured, transparent, and accountable algorithmic governance, may contribute to strengthening collective protection in digitally mediated urban environments. The study adopts a qualitative and exploratory methodology, grounded in a comprehensive review of national and international scholarship, normative analysis of the Brazilian legal framework, and comparative examination of international regulatory models. Constitutional provisions, data protection legislation, technical documents, and institutional reports on digital surveillance were analyzed, alongside concrete experiences involving the implementation of urban monitoring systems. The research follows an interdisciplinary approach, integrating constitutional theory, administrative law, political philosophy, and critical studies on technology and society. The findings demonstrate that facial recognition constitutes a high-risk technology whose use requires more than formal legal authorization. It demands adequate institutional design, ex ante validation mechanisms, independent audits, technical traceability, qualified oversight, and substantial transparency. The application of the proportionality principle—understood not only in its classical formulation but also in its structural dimension—emerges as a central instrument for reconciling public security and privacy, preventing both indiscriminate deployment and abstract prohibition. The dissertation concludes that the proportional limitation of privacy, far from representing an abdication of guarantees, may function as a constitutionally structured mechanism of collective protection, provided it is embedded within a normative architecture capable of ensuring democratic oversight and respect for the essential core of fundamental rights. In doing so, the study offers theoretical and institutional parameters for the construction of an urban surveillance model compatible with the Democratic Rule of Law in the digital age.