The Town Council can exercise a control of the tools of work, among which the electronic mail is found, when this control has the maintenance of the computer and telematic infrastructure of which he orders the Town Council as a purpose, to verify the fulfillment on the part of the workers of its work duties, or to coordinate and to guarantee the continuity of the work activity in the suppositions of absence of the workers. In application of the principle of quality (article 4 LOPD) it is necessary to determine the performances of control depending on the purpose that is pursued in each case and to choose the less intrusiu system for the particulars. It also becomes necessary to inform clear and previously to the workers about its duties, the implanted safety measures, as well as the scope of the control about the tools of work.