The early recognition of ASD in adults is challenging, in particular due to the lack of appropriate and robust diagnostic tools. We performed a psychometric validation and diagnostic accuracy study of the French version of the RAADS-R on a sample of 305 adults: 105 with ASD without ID, 99 with psychiatric disorders, and 103 non-psychiatric control groups. The French version of the RAADS-R demonstrates good reliability and diagnostic validity, suggesting that it can help clinicians during the diagnostic process in adults with ASD without ID. However, the finding that a two-factor structure better fits the results requires further validation. This study point out the need of further study of RAADS in psychiatric disorders group due to the relatively high false positive rate (55.6%) of ASD.