Assuming all battles go as OTL and any differences would come at the negotiating table - the British favored Bourbon restoration, the Austrians were happy to have Napoleon personally abdicate in favor of his infant son, the Prussians wanted France carved up into multiple countries, and Russia had no fixed opinion and tended to agree with the last person who spoke. Discounting Prussia's idea as unworkable, it seems clear enough that Russia could be swayed to Austria's point of view, resulting in a continuing Empire.
I'm confident Napoleon himself wouldn't be permitted to retain the throne under any circumstances. I can't imagine who would favor Bernadotte - none of the four opinions that matter would rate him as a better choice than the ones already on the table, and Britain and Austria don't have positions so irreconcilable that a dark horse compromise candidate need be considered.