CONTEXT Cereal–legume intercropping is a diversification practice that offers many advantages, especially in low-input systems. However, its adoption remains low on European farms, as technical and economic barriers hinder its development. In recent years, an increase in the proportion of arable land cultivated with cereal–legume intercrops has been observed in France. Three areas in particular – in Western, Eastern and Southern France – seem to be particularly dynamic. OBJECTIVE This study aimed (i) to identify the main farm characteristics associated with the presence of cereal–legume intercrops at the national level in France and (ii) to highlight more specific characteristics that could explain the particular dynamics observed in each focus region. METHODS We analysed data from the 2020 French Agricultural Census for 43,968 farms representative of the French arable crop, livestock, and mixed crop–livestock farming systems. Through a literature review, we identified key factors linked to the presence of cereal–legume intercrops and related them to 42 variables in the census. At the national level, the most important of these variables were identified and interpreted using a balanced random forest and a classification and regression tree (CART). We tested the CART obtained at the national level in the Western, Eastern, and Southern areas and conducted a random forest analysis for each area to identify local particularities. RESULTS AND CONCLUSION At the national level, the presence of cereal–legume intercropping was strongly linked to organic farming and the presence of livestock, especially ruminants. These intercrops were prevalent on farms with high feed autonomy for the cattle and sheep. Additionally, they were commonly observed on farms with grain storage, possibly indicating feed autonomy, on-farm transformation, or marketing outside of agricultural cooperatives. The belonging to a farm machinery cooperative was also strongly associated with cereal–legume intercropping, likely because these cooperatives give farmers access to specific machinery and provide opportunities for knowledge exchange regarding their practices. Similar characteristics were identified at the local level; organic farming was pivotal in the Western and Eastern areas, followed by feed autonomy for cattle. In the Southern area, however, on-farm grain storage capacity was dominant, likely due to longstanding efforts to achieve feed autonomy. SIGNIFICANCE This exhaustive study on French farms identified key farm characteristics strongly linked to cereal–legume intercrops adoption. This insight is critical for promoting this practice, whether through national public policies or local farming support services. The methodology proposed can be easily reproduced to investigate other farming practices at different spatial scales.