peer reviewed ; A growing need for objective assessment of colour has been observed in recent years in the field of urban design. In contrast to other building attributes (shape, size or location), which are easy to specify, urban design codes generally define expected chromatic attributes of building façades through indirect regulations considering materials. Some municipalities propose colour charts as guidance tools for urban regulation which present some disadvantages. This obvious lack of affordable instruments in a purpose of characterization or regulation was the main motivation of this research. The aim of this paper is to present a user-oriented protocol which can be applied to characterize chromatic attributes of an urban fragment. The challenge is to provide quantitative answers to these two questions: how is colour organized, how does it develop a structure in the city? The main purpose of the research is hence to investigate stable colour typologies within the city; each urban area (historic center, suburban housing district, commercial zone, etc.) being characterized by a specific colour palette.