Today, with rising urbanization, cities are challenged to ensure the tranquility of citizens while facing drastic budget cuts. CITY ZEN urban security platform was designed to collects and processes a lot of data to alert and anticipate events and plan resources to improve security in public spaces. The purpose of the project is to make the processing of social media flows more reliable to enhance risk events anticipation. Semantic and predictive analysis are algorithms that are used in many fields but separately. The combination of both technologies makes accessible and operational many sources that are virtually available today It complies with GDPR by not storing neither social media messages, nor information about individuals and organisations. Collected data is processed in an European cloud.