Inclusion Criteria for patients :  Age ≥ 18 years and < 75 years Crohn's disease (according to the Lennard-Jones criteria) for at least 6 months Patient in steroid-free clinical remission for at least 6 months under anti-TNF agent (no clinical evidence of flare nor change in Crohn's disease specific treatment (anti-TNF, immunosuppressive, …) within 6 months before inclusion) and CDAI <150 the week before inclusion) and willing to withdraw anti-TNF treatment Female of child-bearing age with an active contraception and this during at least the period of treatment (week 52) Patient with health insurance Informed Written consent  Inclusion Criteria for healthy volunteer donor :  Age ≥ 18 years and < 50 years 17 kg/m² < body mass index < 30 kg/m² Regular bowel movement defined as at least 1 stool every other day and maximum 2 stools per day Subject with health insurance (AME excepted) Informed written consent  Exclusion Criteria for patients :  Crohn's Disease complication requiring surgical treatment Contraindication to colonoscopy or anesthesia Pregnancy or breastfeeding during the study (Cf. Addendum 4) Diagnosis of Crohn's disease restricted to the upper gastrointestinal tract (oesophagus, stomach, duodenum, jejunum) Patient with active perineal disease (defined as evidence of perineal abscess or active draining fistula or presence of seton or presence of perineal ulceration) History of bowel resection Current stoma (Ileostomy or a colostomy) or stoma in the last 6 months or any other intra-abdominal surgery within 3 months prior to inclusion Participation in any other interventional study Patient under legal protection  Exclusion Criteria for healthy volunteer donor :  - For details, please see protocol