Sustainability has become a central theme in contemporary fashion branding, yet the ways in which companies articulate their commitments can vary significantly. This study examines how French ethical fashion brands construct their discourse on sustainability through linguistic choices, focusing on terminology, conceptual associations, and emotional framing. Using a lexicometric approach, we analyze a corpus of brand communications through word frequency analysis, co-occurrence heatmaps, and sentiment analysis. The findings reveal that sustainability discourse is structured around key themes such as materials, transparency, and cultural identity, with a strong emphasis on traceability and responsible production. Despite expectations of aspirational messaging, neutral sentiment dominates, suggesting a preference for factual, credibility-driven communication over overt emotional appeal. The study also highlights how labels and certifications play a pivotal role in reinforcing sustainability claims, though they may also serve as marketing tools rather than verifiable indicators of corporate responsibility. Additionally, the absence of key terms like “upcycling” suggests that linguistic choices shape how sustainability practices are framed and understood within the French ethical fashion industry. These insights contribute to a broader discussion on how sustainability is communicated in fashion branding and raise questions about whether changing geopolitical dynamics and increasing environmental awareness will influence the evolution of these narratives in the future.