In the face of the global shift toward Open Science, policies accelerate cultural change and enable academic institutions, funders, research infrastructures, and publishers to develop their position in the discourse. Policies can reference norms from a wider setting, for example scientific societies or the FAIR Principles. They can also serve as a motivator for researchers to participate in Open Science practices, for example publishing articles Open Access or making code and research data available. However, in order to turn policies into practice, a research-supported infrastructure is necessary. Dedicated repositories facilitate the implementation of these policies, for example by making research output available under open licenses. In this SciDataCon session, we explored how various stakeholders develop research data policies, and particularly the interrelation of policies and research data repositories. Repositories are at the core of data sharing, as they provide the means to store, curate, publish, and preserve research data. Furthermore, they generate, consolidate and maintain metadata, thus supporting the findability, accessibility, interoperability, and reusability of datasets. This topic has led to the creation of various guideline documents and recommendations in recent years, but also to controversial discussions. The session included lightning talks from the perspective of various stakeholders that have developed policies and guidelines for Open Science practices and research data handling, namely research organizations, funding organizations, journals, and research data repositories. These insights were followed by a presentation on the topic of harmonization and standardization of data policies, which is a key motivation for activities in the national and international research data community. The proposed session was organized by members of the DFG-funded re3data COREF project.