concerns the validity of the optimal Riemannian L 1-Entropy inequality Ent dvg (u)≤ n
log(A opt‖ D u‖ BV (M)+ B opt) for all u∈ BV (M) with‖ u‖ L 1 (M)= 1 and existence of
extremal functions. In particular, we prove that this optimal inequality is equivalent to an
optimal L 1-Sobolev inequality obtained by Druet [3].