Yseulys Costes

About Yseulys Costes

Yseulys Costes is a leading French executive in digital marketing and adtech. She founded 1000MERCIS in February 2000, a company that later became Numberly, and helped build it into a listed and international business focused on data-driven marketing, CRM, media activation and customer relationship technologies. She is typically described as Chairwoman and Chief Executive Officer, and her role as founder makes her the central figure in the company’s strategy, culture and long-term positioning. Before launching her company, Costes followed an academic path in management, marketing and strategy. She graduated from the Magistère de Sciences de Gestion and earned a Master’s degree in Marketing and Strategy from Paris-Dauphine University. Her exposure to the United States and to an academic environment connected with quantitative marketing helped shape her early understanding of digital behavior and data-led business models. She also worked in research and teaching, including interactive marketing, and authored books and articles on online marketing and databases. At 1000MERCIS/Numberly, she led the evolution of an internet-era startup into a recognized marketing technology player operating across multiple markets and serving major brands. Available sources highlight her ability to combine technological expertise, business judgment and a strong performance mindset. Beyond her operating role, she also served as a board member of major listed companies, including Kering and Vivendi, which underlines her credibility in high-level corporate governance. Her profile is also marked by sector influence. Frequently sought after by large corporations and public stakeholders, Costes has become a respected voice on digital transformation, data strategy and innovation. Her career reflects the path of an entrepreneur who founded, structured and grew a French technology group while also establishing a strong reputation as a corporate director and governance professional in Paris.