This article examines a particularly interesting inheritance case from late-eighteenth-century France to study the intersection of legal practices and Enlightenment ideas at the end of the Old Regime. The case, involving dispute around the estate of a deceased tax farmer, addresses family relations broadly within the specific context of inheritance and spousal assets. The five briefs produced on appeal to the Parlement of Paris show particular engagement with Enlightenment themes of reason, nature, and sentiment. The family was a locus of particular interest in eighteenth-century France because of its implications for social relations and its connection, through inheritance, to royal sovereignty. However, family law has been primarily studied from the perspective of practices, whereas the present article focuses on ideals. The article argues that the courtroom was an important site where the diverse implications of Enlightenment thought on family law were worked out. The argument that family law was a site for integrating ideals into practices has implications for how we think about the relationship between law and social change, as well as, in particular, the relationship between Enlightenment and Revolution.