This article explores the phenomenon of French–English code-switching within the framework of psycholinguistic theory, offering a comprehensive analysis of its cognitive, linguistic, and sociolinguistic dimensions. Code-switching, defined as the alternation between two or more languages within a single communicative act, is examined through foundational theories from scholars like U. Weinreich, S. Poplack, J. J. Gumperz, and K. de Bot. The study delves into psycholinguistic models, such as Levelt’s speech production framework, which outlines stages like conceptual preparation, grammatical encoding, phonological encoding, and articulation. De Bot’s bilingual lexicon model suggests that lexicons of different languages form interconnected subsystems within a unified framework, enabling seamless code-switching through lemma selection and word-form retrieval. The concept of the matrix language, introduced by F. Grosjean, highlights how bilingual speakers operate in monolingual or bilingual modes, with co-activation of languages facilitating dynamic linguistic transitions. Linguistically, the article addresses constraints like S. Poplack’s equivalence constraint, which ensures structural compatibility, and J. MacSwan’s minimalist approach, which views code-switching as the merging of lexicons within a unified grammatical system. Challenges to rigid constraints, such as the government principle, reveal the flexibility of bilingual speech, influenced by social and pragmatic factors. French–English code-switching, prevalent in fashion and lifestyle media, exemplifies how French terms like laissez-faire, je ne sais quoi, and rendezvous are integrated into English discourse to evoke sophistication and cultural prestige. These terms often function as borrowings or code-switches, reflecting bilingual competence and cultural signaling. Sociolinguistically, code-switching serves as a marker of identity and prestige, particularly in globalised contexts. The article emphasises the cognitive flexibility of bilinguals, as noted by E. Bialystok, and the role of social context in shaping language choice, as discussed by P. Auer and B. Spolsky. Examples from media texts illustrate how French terms enhance rhetorical expressiveness while adhering to English grammatical norms. The study concludes that French–English code-switching reflects a complex interplay of cognitive processes, linguistic structures, and cultural dynamics, offering insights into bilingual communication and its role in modern discourse.