In recent years, public perception and acceptance of Carbon Capture and Storage has become a key issue for research as technological projects have been initiated in USA, Canada and Europe. It has been considered that public opposition could be an important barrier for technological deployment. This report is part of the sub project Acceptability and Governance of CO2 storage processes, started in 2005 as a part of the technological project Advanced technologies of CO2 generation, capture and storage. The study is based on the application of focus groups with lay people. This qualitative social research technique was applied to get a deeper knowledge of the elements influencing the public acceptability of CO2 storage sites. Results indicate that there exists a low level of awareness about the technology among participants. After providing some information about the technology, the initial reaction stays between rejection and ambivalence. A reluctant acceptance appears when significant importance is given to the perceived benefits. The perception of risk from climate change plays an essential role. (Author) 25 refs.