This document shows the public version of the concept for the CityCLIM project. You will find a description of the overall CityCLIM Ecosystem and Workflow representing a high-level structure and big picture of the CityCLIM solution as a blue-print for the system development, including a definition for each CityCLIM platform component and their mutual interaction. This overview is suitable basis for having a deeper look into the City Climate Service Concept and the Generic City Climate Platform Concept describing each service and component including their objectives, purposes, key functionalities, value and benefits. The document ends with the presentation of first laboratory prototypes that show a proof of concept of critical components and the engineering environment including an early validation by the industrial partners.