This French national, multicenter, prospective, longitudinal, observational study will describe the treatment modalities of a cohort of patients with relapsed or refractory follicular non-Hodgkin's lymphoma, with evaluation of the cohort overall and according to the presence or not of MabThera® (rituximab) maintenance therapy. Actively participating physicians will enroll patients and collect therapeutic management data in a real-life setting up to 5 years.