The two main perturbative schemes for the non-linear evolution of large-scale structures are the Lagrangian and the Eulerian ones. The former has been set as a much more powerful technique, due to its property of yielding the exact solution in the plane-symmetric case. We have applied the Eulerian scheme to this plane symmetric case and have reached the exact solution as well, showing that it is not an exclusive property of the Zeldovich approximation, but that the planar symmetry is a quite special gravitational scenario. In addition, a new interpretation of the relationship between both formalisms is presented.