This study deals with the sea-flood risk in a small lagoon called “Etang de La Palme” on the mediterranean coast of Languedoc (south of France). The risk of a sea-flood in this vulnerable area had been analysed through an integrated approach, combining the natural hazard's description with the perception of the sea-flood risk, itself examined through several interviews and an opinion survey. Our study includes a hazard modellisation , based on data of the last highest storms, associated with individual informations obtained through the opinion survey. The gap we have observed between the risk's reality and its perception is not only linked with a high social ignorance of physical processes and management forms, but also with imprecise tidal measures. Hence, to improve the local evaluation of a sea-flood risk and to propose a cartographic presentation of it, we used a hazard modellisation and took some subjective elements into accounts.