Abstract: During the 1870s, Josephine Butler brought her campaign against the Contagious Diseases Acts to Paris, the birthplace of regulated prostitution. While in Paris, Butler and her allies refined their arguments against regulated prostitution using the Paris morals police as their primary example. As they did so, these activists came to increasingly radical conclusions about the danger of police power more generally. However, the French context not only pushed Butler toward greater skepticism regarding the police but also to an increasingly racialized understanding of that danger. In order to play to French natalist fears, Butler argued that reducing police power over female prostitutes was necessary to preserve European racial health.