This paper presents the French national system for monitoring three groups of marine biotoxins regulated in shellfish, implemented firstly in marine production areas by the REPHY REPHYTOX network of IFREMER and secondly at the distribution level through the network of laboratories approved by the Directorate General for Food within the framework of official controls. The European regulations, the nature of the shellfish toxins, and analytical methods used are presented. The sampling procedures and strategy, as well as the results obtained by each of the two systems mentioned, are presented and discussed.