Page "Nullum crimen, nulla poena sine praevia lege poenali" Paragraph 13

However, some legal scholars criticize this, because generally, in the legal systems of Continental Europe where the maxim was first developed, " penal law " was taken to mean statutory penal law, so as to create a guarantee to the individual, considered as a fundamental right, that he would not be prosecuted for an action or omission that was not considered a crime according to the statutes passed by the legislators in force at the time of the action or omission, and that only those penalties that were in place when the infringement took place would be applied.

Also, even if one considers that certain actions are prohibited under general principles of international law, critics point out that a prohibition in a general principle does not amount to the establishment of a crime, and that the rules of international law also do not stipulate specific penalties for the violations.