In the vibrant city of Paris, a seemingly perfect relationship between Clara, a psycho motor therapist, and Ismaël, a music teacher, is put to the test as they navigate their differing cultural backgrounds and await the arrival of their first child. As news of their engagement spreads, it sparks tension within their families, threatening to upend their happiness. The film "Mauvaise foi" explores the challenges that come with loving across faiths, delving into themes of love, acceptance, and identity.