BACKGROUND: The main French language scales evaluating functioning after lower-limb amputation have not undergone exhaustive psychometric validation. OBJECTIVE: A transcultural validation of the Special Interest Group in Amputee Medicine (SIGAM) mobility grades questionnaire, with 21 closed questions, as an administered questionnaire. METHODS: The questionnaire translation, back-translation and original-author validation was followed by a pretest with 5 patients to check comprehension. The psychometric properties of the scale were validated with 49 patients at the definitive prosthesis stage by an investigator via telephone. Criterion validity was evaluated by comparison with the Houghton Scale score and construct validity by correlation between the questionnaire scores and convergent dimensions (performing everyday activities and performing transfers on a numerical rating scale [NRS], 2-min walk test) and divergent dimensions (managing medication and stump skin care on an NRS). Internal consistency was assessed by the Kuder-Richardson Formula 20 (KR-20) coefficient and test-retest reproducibility by the Cohen kappa coefficient. RESULTS: The resulting questionnaire was validated by the original author after the back-translation. It showed good psychometric properties when administered by an investigator as a self-reporting questionnaire, excellent criterion validity (r=0.89, P<0.01), excellent reproducibility (kappa coefficient 0.87) and satisfactory construct validity. The KR-20 coefficient was 0.67. CONCLUSION: The French version of the SIGAM mobility grades questionnaire (SIGAM-Fr) has satisfactory psychometric properties and can be administered in clinical practice.