That is not Depeche but rather
It's gotta be a nutty translation, because in the base game you aren't allowed to play another card of that color.
This is incorrect. In the base game, you can play another card of a color after you've already reached the end of that path. Doing so allows you to move any other pawn of yours forward one stone. It still has to be a legal card play of course.
With that said;
Note: Unlike the base game, a figure on a final field (value 10) does not allow to use further played cards of this color in order to move other figures.This simply means that you cannot do the same thing in the expansion. Presumably because there could still be a legal play for those cards where in the base game those cards would otherwise have no use.