AbstractAlthough international humanitarian law and human rights law were originally intended to operate in different areas of competence, thirty years of visits by human rights mechanisms to places of detention in parallel with visits made by the International Committee of the Red Cross have shown that they are clearly complementary in several respects. First, there is complementarity in terms of action, in that different but not competitive visits are made. Secondly, through the formulation of increasingly precise legal rules there is complementarity in codification. Lastly, there is institutional complementarity through cooperation between the respective bodies. The result is broader and above all more effective protection for detainees — whatever the legal status assigned to them — which, if it cannot entirely eliminate the possibility of torture and cruel, inhuman and degrading treatment or punishment, can at least help to prevent and remedy such abuses.