In recent years, CSR has taken on great importance in the life of companies, which are much more aware of the existing social, economic and environmental problems. So, when Ecommerce has taken an important place in the life of different industries, these companies (especially in the world of textiles) have had to adapt and understand how to exist and use CSR to stand out and enter the market.

The purpose of this thesis is to explore how companies that make online sales of clothing in France can create one or more competitive advantages by using CSR, and analyze the habits and behaviors of French consumers, understand in depth the standards to which French companies face to create a competitive advantage.

The empirical results were obtained thanks to a quantitative study, and a questionnaire of ten questions that could meet the objective mentioned above. The results obtained were then collected and analyzed by the authors in order to find similarities or differences with the secondary data collected previously.

The conclusion of this thesis shows that CSR can become a real competitive advantage, and give real opportunities to online fashion companies in France provided that their implementation is done in good conditions. Customers being more and more attentive to ecological, societal and ethical issues, companies are almost obliged to implement sustainable and ethical practices in their practices, from production to distribution in order to develop.

In summary, the thesis identified consumer resentment towards these CSRs, and the benefits that French online fashion companies can derive from their implementation in the near future.