  We discuss the need of including tensor terms in the effective Gogny
interaction used in mean-field calculations. We show in one illustrative case
that, with the usual tensor term that is employed in the Skyrme interaction
(and that allows us to separate the like-nucleon and the neutron-proton tensor
contributions), we can describe the evolution of the N=28 neutron gap in
calcium isotopes. We propose to include a tensor and a tensor-isospin term in
finite-range interactions of Gogny type. The parameters of the two tensor terms
allow us to treat separately the like-nucleon and the neutron-proton
contributions. Two parameterizations of the tensor terms have been chosen to
reproduce different neutron single-particle properties in the 48Ca nucleus and
the energy of the first 0- state in the 16O nucleus. By employing these two
parameterizations we analyze the evolution of the N=14, 28, and 90 neutron
energy gaps in oxygen, calcium and tin isotopes, respectively. We show that the
combination of the parameters governing the like-nucleon contribution is
crucial to correctly reproduce the experimental (where available) or
shell-model trends for the evolution of the three neutron gaps under study.
