The line is linked to Lucie Aubrac, named for the French Resistance figure whose wartime story was retold in Claude Berri's 1997 film starring Carole Bouquet and Daniel Auteuil. The title phrase itself is much older in French as an expression for treachery done by someone trusted. Online, the clip survives detached from the film's historical plot and is reused as a soundboard shorthand for backstabbing, which explains why a serious period drama line now appears in meme edits and reaction posts.