This paper addresses the liveability and functionality of human habitats, historic city centres in specific, under the conditions of global change analysing the influence of commercial signage in the appearance of historical streetscapes. In many cases, the commercial city centre coincides with the historic core, and the challenge of the local authority is to combine commercial activities with the preservation of historic buildings and public spaces. As part of the historic context of many countries, historic city centres have been through a process of physical transformation, which involves the satisfaction of new social and commercial needs. This transformation usually involves updating of historic buildings to accommodate commercial activities, and the insertion of contemporary architecture in existing streetscapes. This is a common process and there is nothing wrong with that; problems begin when historic buildings and places are harmed by this global change. This paper draws on three empirical case studies in two different countries – England and Brazil - to examine questions of commercial signage control, preservation of historic heritage and user preference and satisfaction with historic city centres on an international stage. The objective is to inform those factors that need to be taken into account in the development of commercial signage controls with regard to the preservation of historic heritage and global changes that affect the appearance of urban sites. The empirical investigation adopted the Environment Behavioural approach, which involves theories, concepts, and methodologies related to environmental psychology, architecture, planning, and urban design. An anonymous questionnaire was designed to analyse user’s satisfaction and preference with the appearance of a set of commercial street facades. Ideally, to ensure maximum realism, users from England and Brazil should observe the commercial streets of each case study on-site. However, because of the impracticality of bringing users from England to Brazil and vice versa, the experiment was based on colour photomontages. A focus group was also applied to explore what a pre-determined group of people think and feel about the relationship between commercial signage and building facade in a specific case study. The discussion was carried out in the case study where the commercial street facades chosen as the worst streets in terms of appearance (by respondents of questionnaire) are located. Nonparametric statistic tests and a content analysis were carried out to analyse these data. Results from the questionnaire showed that common views were found between users from the three case studies suggesting that the development of a general commercial signage approach, which helps national, regional and local authorities of different historic city centres design and implement commercial signage controls, is an essential initiative that should be integrated within urban design approaches. From the focus group analysis the evidence from indicates five factors that can increase visual pollution in historic city centres. These factors can be used in the operation of a general commercial signage approach as negative scenarios that should be avoided by local authorities in different historic cities. This study also identifies eight proposed actions that, according to user perception and evaluation, can improve the appearance of historic city centres, and convince shop owners and members of local communities to support commercial signage controls. These proposals can be used in the operation of a general commercial signage approach as strategies to reduce visual pollution in historic city centres of different urban contexts already affected by this problem.