Many parliamentary systems rely on electoral districts whose boundaries must satisfy strict legal criteria, typically requiring connectedness, containment within administrative units, and near-equal population size. While France offers far less flexibility for redistricting than countries such as the United States, multiple legal maps still coexist for a single département. This raises two key questions: (1) can the full set of legal maps be enumerated for each French département, and (2) to what extent is gerrymandering possible in France?

Building on publicly available geographic and demographic data, the authors enumerates all legal maps of most (but not all) départements through a recursive exploration of connected, population-balanced district configurations. 

Using first-round results from the 2022 French legislative elections, the authors then assess the gerrymandering potential of each département by simulating elections across the full set of legal maps. They introduce formal measures of map diversity and statistical outliers to detect cases in which a given districting plan—current or hypothetical—significantly favors or disadvantages a political party (NUPES, Ensemble, LR, RN). The results demonstrate that several current maps exhibit strong positive or negative outlier behavior. This calls for a specific audit of redistricting in those départements, to examine whether the current map is indeed drawn in a way to advantage or disadvantage some party.