There is an increasing interest in corporate sustainability and how companies should include it to satisfy user's requirements concerning social, economic, and environmental impacts. Research about sustainability in computer science aims to offer methods, techniques and tools to lessen the impact of new technologies on the environment, to offer a better world, a smarter life, to the next generations. Information systems must participate in the collective effort to move towards sustainable development, and software and application companies must lead a CSR strategy to achieve this aim. Moreover, beyond an individual company approach, sustainability should be seen as an integral quality of any software (as well as safety, performance or reliability). All of this seem obvious at a time when applications and programs of all kinds are ubiquitous in everyday life. Nevertheless, the challenges of sustainable development have still not been considered in certain key sectors such as the development of information technology. A lot of ecolabels exist for a lot of different products, although not for software sustainability. We propose in this work an ecolabel for software sustainability, based on a set of relevant criteria found in different works.