This research project is centred on the espionage and information networks of emperor Charles V in France (1525-1550). The research places a specific emphasis on the crucial role played by the Burgundian Low Countries in the processing and dissemination of information within the complex framework of the Habsburg composite monarchy. Additionally, the significant roles of the emperor’s sisters, Mary of Hungary, serving as regent in the Low Countries, and Leonor of Austria, holding the position of queen consort in France, are analysed within the broader Habsburg family network.