Mistakes in general, and specifically in relation to Certificates of Origin, are to be assessed not only with relation to the customs declaration as a whole (jointly with the documents attached to it), but also to the general principles of law (in particular those of material truth, legality, reasonability and good faith) and to the subjective aspects of the customs infractions. Our purpose here is to introduce for analysis all of these combined aspects which are ultimately related to human activities, and to the intervention of the public administration as a participant in international trade law in its control function.