The increasing urbanization results in a rising demand for smart city platforms that optimize limited resources and thus save resources and increase the quality of living at the same time. Several systems have evolved in the past to address such issues by providing platforms for collecting, sharing, and processing urban data. However, these existing platforms only partially address challenges like fostering the participation of citizens, protecting their privacy, and assuring certain levels of quality of information. In this paper, we present the architecture of SANE as an open, citizen-centric, scalable, and privacy-preserving smart city platform. SANE is intended as open platform on which citizens can contribute data but also hardware, without any central authority or control. Moreover, citizens maintain full control on their data and its usage. SANE comes with rich and distributed data analytics functionality that is intended to help citizens to answer data-related question in the context of smart cities.