This document summarizes a session on scaling Internet of Things (IoT) and data marketplaces in Europe. It discusses profiles of data suppliers and users, obstacles to business-to-business data sharing such as vendor lock-in and data availability, and how to address these obstacles by promoting interoperability, traceability and data quality. It also notes that data must be transformed into knowledge through services like analytics, and that existing infrastructure can be leveraged in smarter ways to avoid duplicating costs. The document lists speakers at the session who represent organizations working on IoT, data sharing platforms and smart city initiatives.