Research has suggested that experts differ from laypeople in their risk judgement. This hypothesis converges with a result often demonstrated in studies of beachgoers, who are shown to be generally unfamiliar with rips and underestimate the associated risks. However, no study has attempted to explicitly compare the perceptions made by beachgoers with those made by lifeguards, who are considered to be the experts in this field. In this presentation, we investigate the difference in risk perceptions by laypeople and lifeguards at a beach located in one of the most dangerous coastlines of France