It is an external application, and therefore does not require the ownership of Cinema4D. It's not a plugin. Which means, no connection to C4D.
This application also imports OBJ, FBX, 3DS...etc formats and it is not necessary to have the original applications of these formats!
The SDK therefore does not seem to allow a total independent import of .c4d scenes.
There will therefore be no Cinema4D import/export.
Unless I can get the description on the structure of a .c4d file. In this case, I would write my own import/export library ;)
Of course, the information received will remain confidential.