This paper is to clarify the current status of smart systems and discuss the progressive formation of the privacy protection ecosystem for smart cities in Japan. The authors surveyed representative smart city projects, promotion groups, and several privacy protection platforms as case studies. As a result, the authors obtained the following three findings. First, Smart Grids and Smart Intelligent Transport Systems have been progressing steadily. Second, several proof of concept in privacy protection platforms have started recently. Third, these privacy protection platforms are classified into two types: a centralized model and a distributed model. Therefore, it is important for the progressive formation of privacy protection platforms in smart cities not only to integrate the centralized model and the distributed model with a hybrid model based on the structure of Multi-sided Markets and Freemium business model, but also to examine a trust framework of privacy property to formulate its secured services at a low price, before full-scale smart systems come into use.