Randomized Controlled Multicenter Study Comparing Steroid Therapy Plus Anticoagulants to Steroid Therapy Alone in Deep Venous Thrombosis of Behçet's Syndrome

Inclusion Criteria: 1. Age ≥ 18 years old 2. Diagnosis of BS according to the international criteria 3. First or recurrent deep venous thrombosis diagnosed on imaging (venous ultrasonography , and/or Angio CT scan and/or angio MRI) 4. Written inform consent 5. Women of childbearing potential (WOCBP) are required to have a negative pregnancy test before treatment and must agree to maintain during treatment highly effective contraception (ie, abstinence, combined estrogen- and progestogen- containing hormonal contraception, ovulation inhibitors (Oral, Intravaginal, Transdermal); Progestogen-only hormonal contraception associated with inhibition of ovulation (Oral, Injectable, Implantable); Intrauterine device (IUD); Intrauterine hormone-releasing system (IUS); Bilateral tubal occlusion; Vasectomised partner). 6. Affiliation to a social security system. Patients affiliated to universal medical coverage (CMU) are eligible for the study Exclusion Criteria: 1. Clinical condition, other than venous thrombosis, requiring anticoagulation (e.g. atrial fibrillation…) 2. Active bleeding or high risk for bleeding contraindicating treatment with anticoagulants 3. Isolated superficial thrombosis without concomitant deep venous thrombosis. 4. Pregnancy or lactation 5. Have been taking an oral daily dose of a glucocorticoid of more than 20 mg prednisone equivalent for more than 6 weeks continuously prior to the inclusion visit or taking more than 4000 mg methylprednisolone 4 weeks prior to the inclusion visit 6. Have been taking anti-coagulation therapy for more than 4 weeks prior to inclusion 7. Severe chronic renal (creatinine clearance \<30ml/min/1,73m2) or liver insufficiency associated with coagulopathy 8. Platelet count \< 50 x 103/mm3 9. Change in the treatment with systemic biologic therapy or immunosuppressant therapy dose 1 month prior to inclusion visit. 10. Contraindication to investigational medicinal products (Corticosteroids and direct oral anticoagulant (Rivaroxaban)) 11. Participation to another interventional clinical trial or being in the exclusion period at the end of a previous study