Let's take for example trisoxalato-iron(III). What symmetry elements does it have?
First there is a C3 axis that goes between the ligands. It goes through a face of the coordination octahedron.Second there is a C2' axis perpendicular to the main axis. It goes through an edge of the octahedron.
There are no more symmetry elements, the complex is of D3 symmetry.
