The seminar of the International Platform on Racism and Antisemitism intends to approach racism and anti-Semitism as a global, national and local phenomena, resulting from numerous metamorphoses and historical evolutions. The old forms of racism have not disappeared, but they are now in institutional and systemic mode, and in so-called "cultural" or "differentialist" form. Hatred and rejection of the other are now to be found on social networks (conspiracy theories, often anti-Semitic) and in algorithms.