First we will go over the Fe-IIa atoms.
For this the symmetry axes are the axis through the collinear atoms of Fe-IIa and N.
The diagonal axis are not symmetry axes.
For the Fe-Ia-atoms the symmetry axes are the axes perpendicular to the plane by the Fe-IIa atoms. We also have the axes from one Fe-atom to the counterpart through N and lastly we also have the axis through N and 2 collinear Fe-IIa atoms.