A method for preparing solid microcapsules, comprising the steps of adding under agitation a composition C1 comprising at least one active material to a cross-linkable liquid composition C2, the active material is not an additive to be used in the lubricant, fuel or bitumen industries, drilling sludges or muds, or oil exploration/production, compositions C1 and C2 being immiscible with each other. A first emulsion is obtained comprising droplets of composition C1 dispersed in composition C2, adding under agitation the first emulsion to a liquid composition C3, composition C3 and composition C2 being immiscible with each other, to obtain a second emulsion comprising droplets dispersed in composition C3. Loading the second emulsion in a mixer which applies a homogeneous controlled shear rate to said second emulsion, said shear rate being from 1 000 s-1 to 100 000 s-1, to obtain a third emulsion comprising droplets dispersed in composition C3, and cross-linking the droplets so that solid microcapsules dispersed in composition C3 are obtained.