What is the equivalent of French Travaux Diriges (TD) in Anglo-Saxon Universities ? and who leads them?
Based on the discussion in comments and the Wikipedia article linked to above, TDs appear similar to a "recitation section" at some US universities. At my undergraduate university, the teaching assistant (TA) would get together with some subset of the students of the main lecture course who are assigned to that section and go over exercises assigned by the professor and cover or re-cover things from the lecture that were not very well understood by the students.