It sounds like you're looking for a well-written fanfiction or fanwork featuring the pairing .
The fractured relationship between Assane Diop (the modern Lupin) and Laetitia. lupin x laetitia
The dynamic between Assane Diop and Laetitia is not a traditional romance; it is a Greek tragedy wrapped in a French procedural. While Claire often represents the grounding force of Assane’s past and Juliette Pellegrini represents the unattainable allure of his youth, Laetitia represents something far more dangerous: the possibility of a present that Assane is too broken to inhabit. It sounds like you're looking for a well-written