Cartels agreements are agreements between competitors in which prices are fixed, markets are allocated, production is limited or bids are rigged. They are the most harmful type of violation of regulations, i.e. competition law, and should be treated as such. Competition law are rules, regulations that seek to prevent any form of agreement or action that distorts market competition. The regulatory authority, competition law authority, in the European Union is the European Commission, and the national regulatory authority is the Agencija za zaštitu tržišnog natjecanja. Cartel agreements are hardly visible to the law, so often the process of detecting them and ultimately sanctioning takes a long time, usually up to several years. They represent great damage to the entire market, to participants, including competitors, and consumers themselves who, because of such agreements, have a limited choice of products and services for which they often pay a much higher price than what they would have paid if there were no such agreements. Year after year, the competition law authorities, thanks to great efforts and the development of technology, discover an increasing number of cartels on the market and sanction them according to the damage they cause on the market and their traffic.