International audience; During the early spring of 2020, as the COVID-19 (coronavirus disease 2019) pandemic spread across the globe like a viral tsunami, many countries urgently implemented unprecedented mitigation measures to slow it down, following the example of China, where the disease first emerged at the end of 2019. As a result, more than 3 billion unprepared people worldwide had to cope with living under stringent lockdown measures for weeks or months, depending on the country. Together with the deaths of hundreds of thousands of people from this disease, a frightening emotional shock has touched populations everywhere around the planet. Millions have lost their jobs, others have had their personal lives changed drastically; the elderly, for example, have sometimes been isolated from any visits. To our knowledge, no guidelines to prevent psychological trauma have been proposed, even for the most vulnerable individuals. Nonetheless, before this crisis began, several experts had warned about the potential impact of such measures on the populations’ mental health, based on previous experiences of quarantine, as summarised in a review published, as this pandemic reached Europe and before any lockdowns.1 This warning was confirmed a few days later by the publication of a nationwide study conducted in China reporting that the quarantine triggered a wide variety of psychological disorders.2 In France, one of the hardest hit countries in Europe, a nationwide lockdown started on 17 March and lasted till 11 May. Public health authorities made daily recommendations on how to prevent COVID-19 infection with almost no specific advice on psychological prevention.