In 1920 in France, a law was passed prohibiting abortion, the sale of contraceptives and ‘anti-conception propaganda’. While contraception was legalised in 1967 and abortion in 1975, ‘anti-natalist propaganda’ remained forbidden. This article takes seriously the aim of the French state to prevent the circulation of information for demographic reasons. Drawing from government archives, social movement archives and media coverage, the article focuses on the way the propaganda ban contributed to shaping the public debate on contraception as well as lastingly impacting the ability of the state to communicate on the subject. It first shows how birth control activists challenged the legal interdiction against communicating about contraception (1956–67) without questioning the natalist obligation. It then shows how, after 1968, communication on contraception became a power struggle carried out by various actors (sexologists and feminist and leftist activists) and how the dissemination of information about contraception was thought of as a way to challenge moral and social values. Finally, the article describes the change of state communication policies in the mid-1970s, leading to the first national campaign on contraception launched in 1981, which defined information as a task that women should take on.