Fendrihan has some pictures on their site of the "making of" Klar Kabinett, including a vat full of rose petals/herbal looking stuff. Based on that I highly doubt the scent is artificial.
http://www.fendrihan.com/klars-kabinett-rose-shaving-soap-bars-p-1774.html
http://www.fendrihan.com/klars-kabinett-rose-shaving-soap-bars-p-1774.html