In the context of competition law, the concept of an enterprise includes any entity engaged in economic activity, irrespective of the legal status of that entity and how it is financed. From this definition of the company, we can see its characteristics, which are essentially the economic activity of this entity on the one hand and its legal independence on the other. Any conduct in the market can only be considered if the undertaking concerned carries out an economic activity, i.e., an activity of production, distribution or import and export. It must also be independent of other companies in the same market. In other words, each company must be in a position to compete with the other to create perfect competition in the market. Therefore, competition law prohibits anti-competitive practices only if economic and independent entities commit them. Through this study, we will highlight the concept of the institution in competition law, whether from a legal or economic perspective, and we will learn about the conditions for applying competition rules to the institution as a key element in the market.