How to determine real type of Geom_Curve-handles?

Hi there!

When exploring the edges of a TopoDS_Shape (e.g. loaded from an IGES file), I convert the edges to handles to Geom_Curve.
Since I have no knowledge about the structure of the loaded IGES-files, I cannot make any assumptions on the true type of geometry making up different edges, and therefore cannot safely cast the Geom_Curve-handle to something more specific.

Any ideas on how to find out, if my Geom_Curve-handle points to a line, arc, BSpline, bezier or whatever?

Thanks in advance for any help!