Microservices is an architectural style that promotes structuring an application as a collection of loosely coupled fine-grained services. Since each microservice typically accesses different data, while composing complex applications it is hard to monitor which data are getting accessed in the entire application workflow. This raises a serious concern over the privacy protection especially in such a domain as health care. In this paper, we propose a formal Event-B based approach to analysing privacy preservation constraints in the applications developed in the microservices architectural style.