Abstract: The present invention lies within the field of colloidal assemblies and relates to a system for producing solid clusters of microparticles, characterized in that it comprises at least: a fluidic device comprising at least: an element for producing primary droplets, comprising an outlet of width l1 and a main channel for forming solid clusters, having a main axis, of height h2 and comprising an inlet of width l2; said element for producing primary droplets being connected to said inlet of said main channel, h1 being less than h2, so as to form a step between said element for producing primary droplets and said main channel and l1 being strictly less than l2; a system of physical initiation of polymerization capable of initiating polymerization in said main channel.