Recent literature sets forth the positive role of migrants in international trade and foreign direct investment. We use a new database on French migrant associations together with data on the stocks of migrants to diffe-rentiate between organized and, respectively, non-organized migrant-based networks. We find that the creation of a new association of migrants is accompanied by important jumps in bilateral trade and investment between the host and origin countries. This effect adds on top of the impact of non-organized migrant communities, documented in the literature. Non-organized networks affect trade via preference and information channels, while organized networks play mainly an informational role.