In Kantian's argument, actions towards human beings should be in a way as an end in itself and thus respect the autonomy of human beings. In this case, lying to Nazi is permissible since the action displays the respect to the Jews considering telling the truth would lead to the severe consequences of death. Doing so shows consideration towards Jews’ lives and their autonomy. Nazi, in this case, is not worthy of being respected since their intention of harming the Jews makes them immoral. This strategy is not entirely consistent with the Formula of Humanity since it is difficult to decide between which autonomy is worth to be respected and in some scenarios the decision process of lying or not is extremely hard to make. If everyone lies to the Nazi that there is no Jews hiding in their houses, Nazi would start questioning and thus maybe even forcefully enter the house to search and this would lead to a more disastrous result for the Jews despite of the good intentions of protecting them.