According to the product catalog the secret resides in the organic Argan oil from Morocco...
"Argan oil has always been known for its amazing benefits for the skin. The fruits of the Argan tree are left to dry in the sun. The seeds are then collected and pressed to extract the oil. Even to this day this process is still done by hand by Moroccan women...the oil used in the Yves Rocher prodects is from the most recently collected fruits."
One of the distictives of this "oriental soap" in comparison with others is that it uses a blend of Argan and Olive oils, both of which have similar properties when used in cosmetics.
I also found this little bit of trivia in the product catalog...
"The secret of the beauty of Moroccan women. It is known that in the Hamams the women achieve a very soft skin thanks to the oil of Argan. The secret of their velvety textured skin and the shine in their hair resides in the Moroccan clay called "ghassoul". To calm the mind, the Moroccan women apply the perfumes of essential rose oil and essential orange blossom oil (Azahar). Yves Rocher has selected these ingredients to create the fomulas for the "Tradition de Hammam line..."(note - I´m translating from Spanish in these quotes)
The prices in this line of products seemed to be quite affordable in comparison to other Argan products that I have come across, even those sold in Morocco.
One of the most striking images that I have seen of this tree species is of goats climbing the tree to eat its fruits.