Objectives Cultural differences between the USA and France led us to examine the feasibility, acceptability and preliminary efficacy data on craving, quality of life and psychological flexibility of the add-on Mindfulness-Based Relapse Prevention (MBRP) programme in alcohol use disorder (AUD) in France. Design We conducted a prospective observational study with a 6-month follow-up. Setting The study was performed in a naturalistic setting with adult outpatients from an addiction department. Participants We included all patients with a current AUD who participated in the MBRP programme (n=52). There was no non-inclusion criterion. Interventions The intervention was an 8-week MBRP programme, combining elements of traditional relapse prevention cognitive behavioural therapy and mindfulness meditation training. This was an eight-session closed-group programme. Primary and secondary outcome measures Primary outcomes were the number of attended treatment sessions, home practice frequency and dropout rate. Secondary outcomes were changes in craving, quality of life, psychological flexibility, drinking outcomes, depression, anxiety and mindfulness levels. Results The average number of completed sessions was 6.6 (SD: 1.9). Most participants introduced mindfulness meditation into their everyday lives: 69% and 49% of included patients maintained formal practice at 3 and 6 months, respectively, and 80% and 64% maintained informal practice at 3 and 6 months, respectively. Most participants used mindfulness techniques to face high-risk situations (56% at 6 months). Participants reported a significant reduction in craving, days of alcohol use, depression and anxiety and an increase in mindfulness and psychological flexibility at 6 months. Conclusions The MBRP programme showed good acceptability and feasibility. MBRP seemed to improve craving, mindfulness and psychological flexibility. Comparative studies are needed to evaluate the programme’s efficacy in AUD. Trial registration number 2200863 v 0.