If you own Cinema 4D Visualize or Studio you will have the additional option of
Once a file is selected, Cinema 4D will use the information contained in this file to define the light’s emission behavior. The IES light’s parameters can be modified in the Attribute Manager’s Photometric tab.
Here you can modify the IES light’s Photometric Intensity, Photometric Data and Photometric Size settings or you can use the light source’s standard sliders to adjust the light. At the bottom you will find a field that contains information from the manufacturer regarding the IES light’s properties.
In the following image is a lamp from the Polygon Modeling Tutorial whose light is simulated by an IES light. Different IES files will result in different lighting, which can best be seen on the light’s visible cone, but can also be seen on the resulting highlight on the object(s) it illuminates.