Now that I know that the developer parodinal does give very faint colors when used to develop C-41 films, I decided to make a parodinal containing more Acetaminophen than usual to be used as a multipurpose developer. I exposed today a Kodacolor 200 roll and I developed it in this new parodinal in dilution 1:25 at about 40ºC for 7 minutes.
I was positively surprised with the results. It is not color in the common sense it is something between color and sepia. Not an alternative to C-41, but a new photographic approach for hobbyists.