Screening is a crucial step in the cascade of care for people who smoke tobacco or cannabis. In France, general practitioners (GPs) are considered a pillar of tobacco control, and under National Authority of Health guidelines, they are expected to systematically screen their patients for tobacco use. We aimed to assess the frequency of tobacco and cannabis use screening by French GPs and to identify characteristics associated with more frequent screening. From a nationwide random sample of GPs, we estimated the prevalence of self-reported systematic tobacco and cannabis screening. Using logistic regression models, we identified characteristics of GPs associated with systematic screening. Our study sample comprised 2412 GPs, 74.6% of whom systematically screened their patients for tobacco use, and 34.7% for cannabis use. Systematic tobacco screening was associated with being under 50 years of age, working in a group practice, and using the "early identification and brief intervention" approach. Systematic cannabis screening was associated with being 50–59 years old and using the "early identification and brief intervention" approach. This study highlighted improvements in tobacco and cannabis screening frequencies in comparison to previous French data. Better GP training is an essential lever to ensure these positive trends continue.