The paper aims to identify the factors influencing the use of the definite and the indefinite article in thetic (communicatively one-member) sentences of the German language. Statements of this type are characterised by the presence of the focus exponent and the absence of topicalised elements. The scientific novelty of the study lies in identifying the conditions under which the definite article is used in a sentence with new information along with the indefinite article. As a result, by using descriptive and transformational methods, it has been shown that the choice of the article depends on the logical meanings conveyed in the statement (uniqueness or universality), extra-textual factors (symbolism of the named subject) or on the degree of inclusion of the recipient in the fabula space of the narrative: the definite article makes it possible to consider the object as an element of the general situation in the field of view of the speaker-observer, indicating the obviousness of his/her position/condition, while the indefinite article marks a narrative that is somewhat detached from the recipient, although sentences of this type do reflect the perception of the observer.