In today's society, issues such as climate change and resource scarcity are of great importance. What can be done to mitigate climate impacts and make our world more environmentally friendly and innovative? Smart City is a term that has not yet been uniformly clarified. But it is clear that cities which are developed or built according to Smart City concepts are significantly more environmentally friendly, efficient and digitally positioned. Cologne is the fourth largest city in Germany and is a pioneer in topics such as the expansion of emission-free mobility, especially in public transport. In addition, several smart city projects that the city has carried out with cooperation partners are considered innovative projects with a promising future. However, there is a large amount of traffic in million inhabitants city, which repeatedly leads to concentrations of air pollutants that exceed the limit values. One key focus of the city is reducing traffic and thus reducing air pollutants at the same time. As part of its Green City Master Plan, numerous measures have been initiated that have successfully improved the air quality and reduced traffic. The first steps of a smart city development have been developed and implemented and will be further advanced in future. Cologne proved to be the ideal city for the thesis of this work: "Investigation of Smart City Concepts for the Improvement of emission-free Mobility - The Example of the City of Cologne".