"It speaks for the psychology of the war-experienced Romans that they granted the returned triumphant general a victory procession through his town, where he could experience his own deification in the state ... This apotheosis of the victor, the cult of success, of divinity through battle, and of happy success is part of the sociopsychological inheritance of humanity from antiquity..." (Peter Sloterdijk, Critique of Cynical Reason, 1983).
We are so used to certain types of monuments, to certain symbols, that we tend to forget what they signify. Triumphal arches are, in essence, as their name indicates, a glorification of the victory in military campaigns, that is to say, a praise to the use of violence. Not surprisingly, if you observe the details decorating these arches, you will find many victorious heroes of these battles. But also, if you look more carefully, a few defeated. From this dichotomy, and with the intention of reclaiming the memory of these vanquished, in a similar way as John Berger did (Ways of Seeing, 1972), one possible exercise of détournement would be to reconfigure these monuments showing their shadow parts: those marginalized by the official history, the history of the defeated.
Image after Carlo Marochetti's The Battle of Jemmappes (bas-relief, 1845) [pd] in the Arch of Triumph of the Star, Paris and Chantal/Iris' vintage postcard [fu/fd].