Stéphane Joost (research and teaching associate at LASIG) shares his experience in data publication. It includes three cases with unexpected facets: - Publishers’ requirements: what to do when publishing data is compulsory, whereas the data provider prohibits it? - Case of the cartography of a wildlife reserve in Namibia: it is important to publish in open access to share knowledge on the reserve. However, this kind of information can lead to bad use by poachers. How to find the right balance ? - The Nextgen data case: balance between the interests of the scientific community to access the data and the needs of data producers to receive recognition for their work.