Since the legalization of the prostitution sector, not only has the combating of human trafficking through criminal law been substantially fortified, but also the administrative approach to human trafficking in that sector. This integral approach of human trafficking, in which administrative and criminal law measures complement each other, is necessary to combat this harrowing type of crime. The criminal law-administrative approach offers good footholds for a more forceful reaction to human trafficking. Besides the preventive effect administrative measures can have as a complement to criminal law, administrative supervision can also be useful to obtain criminal law information. However, that brings several new dilemmas with it that are connected to the phenomenon of the blurring of spheres. Under certain circumstances, the blurring of spheres between a criminal law and an administrative approach can lead to an improper use of competencies. We conclude that in the manner in which the prostitution sector is currently supervised, the legal protection of the citizen against actions of the supervisor is inadequately guaranteed. That does not mean that information that is obtained through administrative supervision may no longer be used in criminal cases. It is to be recommended however that several changes be made to current practice, which may prevent the improper use of supervisory competencies in prostitution controls.