Fecal Microbiota Transplantation in Crohn's Disease as Relay After Anti-TNF Withdrawal

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 more than one small bowel resection or small intestine resection \> 1 meter * 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