  For the L2 supercritical generalized Korteweg-de Vries equation, we proved in
a previous article the existence and uniqueness of an N-parameter family of
N-solitons. Recall that, for any N given solitons, we call N-soliton a solution
of the equation which behaves as the sum of these N solitons asymptotically as
time goes to infinity. In the present paper, we also construct an N-parameter
family of N-solitons for the supercritical nonlinear Schr\"odinger equation, in
dimension 1 for the sake of simplicity. Nevertheless, we do not obtain any
classification result; but recall that, even in subcritical and critical cases,
no general uniqueness result has been proved yet.
