On Tuesday, March 17, 2020, at noon, France became the third European country to impose a nationwide containment policy in the fight against epidemic coronavirus disease 2019 (COVID-19) viral infection. Announcing that the country was at "war," President Macron called upon all to play a role in mitigating against further development of contagion. This extreme measure never seen before during peace time was the result of adapting not only the French Pandemic Influenza Plan (PIP) being applied to the national context but also real-time clinical, epidemiological, and scientific information about the evolution of COVID-19 infection in the country. The situation was further complicated by local municipal elections and political agendas by populist opinions. Despite mass communication about the importance of individual behavioral attitudes to counter disease propagation, few heeded government advice. Consequently, the situation rapidly deteriorated with increasing number of cases that started to overwhelm health services. As a result, decisive and immediate action was taken by the State for the national public health interest. This report from the field details the timely events that contributed to this extreme policy decision taken by France. A policy decision that other Western democracies have since applied as the pandemic disseminated across the globe.