Cities are complex systems rapidly evolving in a context of strong interweaving between problems and solutions especially in developing countries. The architectural design and the city management processes are renewed by the eruption of sustainable development. These processes are multi-scale: new geographical, temporal and political scales are emerging, calling for new tools for monitoring architectural and urban environmental changes, for implementing comprehensive plans, or for communicating between practitioners. Number of communities in developing countries has taken initiatives to develop tools based on sets of sustainability indicators. But are these tools really helpful during the architectural design or the urban management processes characterized by complexity, fussy or lacunar data, various time and space scales and multi-actors decisions? We will demonstrate in this paper, that these systems, aiming at "a posteriori" diagnosis, cannot be used directly during these fuzzy processes, especially during their early phases very critical with respect to solutions. By adjoining them multicriteria decision support techniques, they may become powerful tools for decision support. Architectural and urban designs may be evaluated using a set of weighted environmental criteria and methods to aggregate the various dimensions involved. Some Electre methods based on the comparison between pairs of solutions have been successfully used in that sense. A step further away may be performed from decision to evaluation support tools, by comparing ongoing urban designs against convolutions of systems of practitioners' values. This "value focused" approach, combined with the Electre-Tri method has been successfully integrated for evaluating the performance of urban projects, according to their distance to various user-defined systems of values.