Taking stance in the field of exhibition history studies, this article contends that the role of exhibitions cannot be understood without considering the artworks and the ideas on art that lay beneath them. It contends that in the early 20th century already, artists of the avant-garde (but not merely them) became aware that exhibitions could supplement and exceed artworks, and thus could modify uses and concepts associated with art, meeting their desire to enlarge the field of action and the efficacy of art. In other words, exhibitions related to artworks in a way similar to the concept of "parergon" proposed by Derrida: they fill a lack in the "ergon" (the work). The essay suggests that public group exhibition could indeed fulfill certain utopian desires that avant-garde artists projected onto the works, but which the latter could not achieve on their own: the desire to move beyond individual authorship, the desire to reach wider audiences, the desire to (be) propel(-led into) history. Thus, considered as parergon, the exhibition fills a triple lack in artworks: lack of public space, of operational time, and of discourse; in doing so, it actualizes the utopian impetus of avant-gardist projects.