yes, the red legs exclude a whole bunch of species with yellow/orange lines on the back. Also, most Arctiinae caterpillars look different in their last stage than
in the ones before. I have some suggestions from what I've seen in the "Bestimmungshilfe", but it needs confirmation/correction:
The most likely candidate I've found is Arctia villica: http://www.lepiforum.de/lepiwiki.pl?Arctia_Villica
(scroll down to "Jüngere Raupenstadien", younger caterpillar stages)
Others are Chelis maculosa and the two Spiris species, but there are no photos of younger stages of them in the Bestimmungshilfe yet.