Inclusion Criteria:

• adult women who are between 18 and 72 years of age
• had a diagnosis of localized breast cancer of any type, and who have completed their treatment (surgery, chemotherapy, radiotherapy) within the last 15 months, or still undergoing hormone therapy or nearing the end of their Herceptin treatment.
• French-speaking
• covered by the French Social Security system or benefiting from a similar health insurance system

Exclusion Criteria:

• A cancer diagnosis other than breast cancer, or a relapse/metastasis of breast cancer, or generalized cancer,
• A medical contraindication to exercise (a medical certificate of absence of contraindication to the practice of physical activity will be required, as for all physical activity in community settings).
• Significant visual or auditory problems or behavioral problems that make it difficult to participate in group physical activity sessions.
• a plan of moving away from the study site.
• participating in another clinical trial
• Male sex