Frenchy Pilou becomes lazy. He doesn't translate within ten seconds anymore... Hehe.
So I'm gonna try to do it... ;-)

Steph has created a lot of objects and scenes with MoI and C4D. Everything works great when exporting in OBJ format. There's no better format for export from MoI to C4D.

You can export MoI curves to C4D by using AI (Illustrator) format. It works great but only for planar curves. You can then easily create your objects like you would do with the "NURBS" curves of C4D.

You can not export curves from C4D (unless maybe by finding and using a plug-in that would allow export in AI format). Steph doesn't see any interest to do that because he finds that MoI curves are 100 times better. Do everything into MoI, especially the curves. Just re-think your workflow and everything will be fine...

Hope this helps...