The HARMONY project supports and enables several metropolitan areas to lead a sustainable transition to a low-carbon new mobility era. For city logistics, innovative services and developments can serve as promising solutions to reduce greenhouse gas emissions and energy consumption in metropolitan areas. The focus of this paper is on the importance of co-creation to achieve the desired reduction in emissions, including both engagement activities and (small scale) demonstrations. The constant and simultaneous involvement of cities, service and technology providers, research entities but also the civil society, is crucial for identifying success factors and lessons learnt.