Follow these steps to install the legitimate Octane plugin for C4D R23.
While there isn't a completely "unrestricted" free version of Octane Render for Cinema 4D R23 Octane Render For Cinema 4d R23 Free Download-
To install Octane in Cinema 4D R23, you must use the specific plugin version labeled for OTOY • OctaneRender: Demo Follow these steps to install the legitimate Octane