  We construct a large class of ${\cal N} = 3$ Janus ABJM models with mass
deformation, where the mass depends on a spatial (or lightcone) coordinate. We
also show that the resulting Janus model can be identified with an effective
action of M2-branes in the presence of a background self-dual 4-form field
strength varying along one spatial (or lightcone) coordinate.
