We extend the optimal taxation framework by Saez (2002) to allow for alternative concepts of justness. We calculate weights of a social planner's function as implied by the current German tax and transfer system based on the concepts of Minimum Sacrifice and subjective just incomes from survey questions and compare them to the welfarist case. We use new questions from the German Socioeconomic Panel (SOEP) to obtain information about what amount of taxes individuals consider as just. We find that the German system is not pareto-optimal as it implies negative weights for working poor under the welfarist approach. Minimum absolute and relative sacrifice are the only concepts of justness that do not imply negative social weights for at least one income group.