Biological effects have been reproducibly reported in rodents exposed to radiofrequency fields (RF) without significant change of the body temperature. These observations relaunch the controversial question of non-thermal effects of RF. If true, such effects would imply to consider RF energy absorption/interaction in tissues, not as volume-averaged, but locally down to the microscale, which is of potential consequence in particular at frequencies beyond 3 GHz. We propose study protocols to explore that question.