Healthcare is considered as one of the most promising areas where big data can be applied to foster innovation for the benefit of patients and of the whole system. Healthcare analytics have the potential to accelerate R&D, increase knowledge on diseases and risk factors, improve treatments, develop personalised medicine, help physicians with decision support systems… The access to data is also a driving force for patients' empowerment and for the democratic debate. However, there are also concerns about the societal, economic and ethic impacts of this wave of digitization and of the growing use of data, algorithms and artificial intelligence. Given the issues at stake, collecting and analysing data generated by health care systems is a strategic challenge in all countries; in that respect the French National System of Health Data (a national data warehouse linking data from several sources and giving a vision of the care pathways for the entire population, with a ten-year history) is an asset, but it has to be completed and enriched with data from electronic health records.