Abstract Background ETHER (“Education THEérapeutique pour la Réduction des dommages en alcoologie” or Therapeutic education for alcohol-related harm reduction) is a multicentre community-based mixed-methods study, which aims to evaluate the effectiveness of the innovative therapeutic patient education (TPE) programme ‘Choizitaconso’ in a sample of French people with alcohol use disorder (people with AUD). Choizitaconso teaches people with AUD psychosocial skills to help them (re)establish controlled drinking and reduce alcohol-related harms. Recruitment started in October 2019. We present here the protocol of the ETHER study. Methods ETHER’s quantitative component involves a 6-month controlled intervention study which evaluates Choizitaconso’s effectiveness by comparing 30 people with AUD following the programme with a control group of 60 people with AUD not enrolled in it, using a questionnaire co-constructed by the research team and members of the people with AUD community. Thirty-four alcohol-related harms are assessed and summed to provide an individual measure of the ‘harm burden’ from consuming alcohol (primary outcome). Secondary outcomes are anticipated and internalized stigma, alcohol consumption measures, craving for alcohol, coping strategies, health-related quality of life, self-confidence to control or abstain from drinking, treatment self-regulation, anxiety and depressive symptoms, alcohol-related neuropsychological impairments, and capabilities (a measure of wellbeing in adults). Data will be collected in face-to-face and phone-based interviews at enrolment and 6 months later. Linear regression models will be used to assess the impact of the TPE programme on changes in the primary and secondary outcomes, while adjusting for other correlates and confounders. The study’s qualitative component comprises semi-structured interviews with 16 people with AUD who have already completed the TPE programme at least 6 months before the interview. Qualitative interviews will be analysed using thematic analysis. Results and conclusions ETHER is the first evaluation study of an innovative TPE programme specifically designed to reduce alcohol-related harms and reach controlled drinking in France. The involvement of the people with AUD community in selecting which experienced and perceived alcohol-related harms to measure ensures that ETHER will provide healthcare staff and researchers with a relevant set of harm reduction criteria for use in future research. Finally, ETHER will provide scientific justification for implementing novel alcohol-related harm reduction approaches and champion controlled drinking as a therapeutic goal. Trial registration ClinicalTrials.gov, NCT03954054. Registered 17 May 2019—Prospectively registered, https://clinicaltrials.gov/ct2/show/NCT03954054?cond=alcohol&cntry=FR&city=Marseille&draw=1&rank=1.