  We give a characterization of nearly free plane curves in terms of their
global Tjurina numbers, similar to the characterization of free curves as
curves with a maximal Tjurina number, due to A. A. du Plessis and C.T.C. Wall.
It is also shown that an irreducible plane curve having a 1-dimensional
symmetry is nearly free. A new numerical characterization of free curves and a
simple characterization of nearly free curves in terms of their syzygies
conclude this note.
