In Chap­ter 23, titled “The Art Thief,” the com­plex rela­tion­ship between Anne-Cather­ine and Bre­itwieser unfolds as she faces a dire ulti­ma­tum: it’s either him or the art. Their love is entan­gled with crime, com­pli­cat­ing Anne-Cather­ine’s feel­ings about their life togeth­er. Despite know­ing the con­se­quences of Bre­itwieser’s actions, she acknowl­edges that she wants to remain with him, demon­strat­ing her will­ing­ness to com­pro­mise even amid the chaos.

Anne-Cather­ine pro­pos­es a truce—a less fre­quent and more cau­tious approach to theft, with Switzer­land entire­ly off-lim­its due to their pre­vi­ous arrest. Bre­itwieser agrees, but the allure of art proves too strong. Dur­ing a Paris trip, despite their arrange­ment, Breitwieser’s desire leads him to steal a paint­ing from an auc­tion house with Anne-Cather­ine as the look­out. This time, they evade cap­ture, and he feels invig­o­rat­ed by the adren­a­line of steal­ing.

In the days fol­low­ing their heist, Bre­itwieser can’t sup­press his com­pul­sion to steal, and Anne-Cather­ine’s ini­tial com­pro­mise only fuels his crim­i­nal activ­i­ties fur­ther. As they trav­el through France, he claims more art, dis­miss­ing her con­cerns. Their dynam­ic, as ana­lyzed by César Redon­do, a ther­a­pist, high­lights a trou­bling pow­er imbal­ance, sug­gest­ing Anne-Cather­ine is not mere­ly an accom­plice but a vic­tim of emo­tion­al and pos­si­bly phys­i­cal abuse from Bre­itwieser. Despite this, obser­va­tions from those who know her sug­gest she is not the weak link in the rela­tion­ship; she has a sta­ble job and enjoys some sense of agency.

How­ev­er, their rela­tion­ship dras­ti­cal­ly changes when Bre­itwieser dis­cov­ers a med­ical bill reveal­ing that Anne-Cather­ine had under­gone an abor­tion. Feel­ing betrayed by her secre­cy, he con­fronts her in a fit of rage, slap­ping her in a moment of uncon­trolled anger. The after­math leads Anne-Cather­ine to leave, return­ing to her par­ents’ home, sig­nal­ing a sig­nif­i­cant turn­ing point in their tumul­tuous union marked by art, theft, and emo­tion­al tur­moil.