  We solve Teissier's proportionality problem for transcendental nef classes
over a compact K\"ahler manifold which says that the equality in the
Khovanskii-Teissier inequalities hold for two nef and big classes if and only
if the two classes are proportional. This result recovers the previous one of
Boucksom-Favre-Jonsson for the case of nef and big line bundles over a
(complex) projective algebraic manifold.
