The work addresses the issue of the treatment of mixed contracts in connection with the trade tax addition. Using the example of event companies such as concert, trade fair, and travel organizers, the author discusses various contractual arrangements that arise in legal transactions, which encompass a variety of different services, such as hotel procurement contracts, from a civil and tax law perspective. The study is characterized by its high practical relevance and timeliness. It effectively engages in a detailed and critical examination of the existing spectrum of opinions in case law, literature, and tax administration to develop new ways of thinking and solutions for dealing with mixed contracts. Additionally, it sheds light on previous approaches to qualifying immovable assets as fixed assets and seeks the necessary frameworks in this context.