Sustainability is a topic paying a visit to most industries today and the fashion business is no exception.The development of eco-efficient stores is one of the efforts carried out by Inditex Group with the aim to adopt sustainability into its practices. Such stores distinguish themselves for saving electricity, water and by greatly reducing the amount of CO2 that is yearly produced. The concept was initiated with the Zara brand but it will be introduced to the other six brands that integrate Inditex as well. However, despite the reduction in the carbon footprint it cannot be denied that the fast fashion business model creates a paradox in terms of sustainability.The following is a case study on the Zara Rome eco-efficient store. Being a store benchmark in Europe, it explores how the sustainability concept is communicated through this model and if the identified paradox is addressed. To do so, the study analyzes the external, internal and interactive marketing of the eco-shop based on the service marketing triangle theory and the Mehrabian-Russell stimulus-response model used in visual merchandising. Participant observation on site and a content analysis of relevant documents were carried out as research methods in order to find the messages emitted on each side of the triangle.The analysis shows that the paradox in the Zara eco-shops is not being handled at the customer level, though it is being handled at internal and external levels. As a conclusion, the eco-shops effort is part of a sustainability strategy with long term perspective and it will be addressed at customer level when the company as a whole counts with a more sustainable brand identity. Additionally suggestions are offered to potentialize the communication of sustainability in an eco-shop. / Program: Master in Fashion Management with specialisation in Fashion Marketing and Retailing