Looks like every DCC app. has different exporter/importer. Since file format was updated by years, added some attributes, some removed etc.Some importers are more "benevolent" to absolute paths in material definitions, c4d importer just "read" data and "believe" paths to image files. Would be good to know which parameters are read by c4d importer and adjust source mtl file to it´s needs.
Other question is if importer recognize different map channels and put these images into appropriate material channels (mean color to color, diffuse to diffuse, bump to bump etc.) @hvanderwegen example use just single color channel. Would be good to have some example with different maps not just color/diffuse.
btw, @hvanderwegen Thanks for example file. Yes, updating paths in mtl file and checking invert transparency option in obj importer will load object together with textures. (sure, could be edited mtl file directly changing attributes value and leave c4d importer on default preset, but this is another story)