In Emily Temple's article about "The Disturbing Origins of 10 Famous Fairy Tales", published in Flavorwire.com, she wrote about the unsavoury original or older versions of our most favourite fairy tales. These were the versions that had been passed around from the Grimm Brothers' compilation of fairy tales and before it was sweetened (a tad bit) by another compilator named Pullman and long before Disney thought of sugaring the plots and presented the stories to us so that they carry some kind of moral lessons, which would make us feel good and, consequently, get more of our money in the form of merchandise marketing. :-P
In any case, one of those ten fairy tale stories is the story of the "Frog Prince." The story, as we know it, is quite simple: "the princess kisses the frog, out of the goodness of her heart, and he turns into a prince." In the Grimm Brothers original version, the frog tricked the resentful princess into making a deal with him. Then he relentlessly followed her until she got to her castle and even ensconced himself onto her silken pillow. She throws him against the wall and voila! Damn frog turned into a prince! (And darn it, he's handsome, he's dashing, he's rich! For Pete's sakes, he's a prince? Isn't that the dream of every girl in the whole world? To meet a handsome rich prince? Ah, wait, she's already a princess. Never mind!) But the trickery and the mild violence aren't just that. There were other earlier versions of the story where she cut off his head instead. Well, that doesn't even come close to the romanticism of "the kiss", does it?
I'm thinking the Princess must've been French and just wanted a good "cuisses de grenouille à la Provençale".