In this Article, the author explained one of the basic principles of Criminal law - their ultima ratio character as a part of the legitimacy policy. The last resort has been presented as an important method in the law-making process, as well as in its application. Thus, both the parliament and judicial authorities should start from the main purpose of Criminal law, avoiding extensive usage of punitive mechanisms in general and not allowing the prevalling influence of "punitive populism". These theoretical postulates are presented as a fundament for the analysis of the criminal offence Construction without a building permit which is prescribed by the article 219a of the Criminal Code of Serbia. The author showed some imperfections of positive provision such as "the attack on lex certa" as a part of legal principle through the shortcomings of the legislative technical regulation; potential misunderstanding of the "building permit" meaning; restitution claim non-use, despite it can bring some economic benefits. Also, it was emphasized that the same conduct from the Art. 219a CC is (at the most) prescribed by secondary law (Planning and Construction Law) as a commercial offence, which can have proceeding impact onne bis in idem principle. The protected object is vague because "the property" is a little bit far away of administrative procedure which is substantially contained in the following provisions. Also, we point to praxis which is created by public authorities.The potential problem with this incrimination can be non efficiency influence on those to whom is addressed. In the future, the legislator may think about decriminalization of this offence through transforming it in commercial offence or misdemeanor. If it is a "big step" from the sociopolitical aspect, the space for improving current norm will be still opened in a legislative technical way.