Big data is critical for the operation of AI and expert systems. At the same time, data is not free of regulation. In the EU, the General Data Protection Regulation entered into force last year, and it is set to revamp entirely the way private and public organisations process data. At the same time, data posted on Internet platform brings about complex trade-offs between free speech and privacy. Last, but not least, in the legal tech field, the training data on which legal analytics tools work generates interesting challenges in terms of representativeness, neutrality and anonymity.