Even without studying facial traits in details, Napoleon III's blue eyes and blondish beard don't look particularly Corsican.
19th-century people wouldn't have known that, but it would have been extremely improbable genetically for Napoleon III to have been Louis Bonaparte's son, because all seven siblings of Napoleon Bonaparte and both his parents had brown eyes, which means that all would have had two copies for brown eyes. In order to have blue eyes both parents need to contribute one blue eye allele.
This also makes me wonder whether
Napoleon II was Napoleon I's biological son. This case is even more suspicious since the boy had both blue eyes and blond hair and looked nothing like his father. I have always suspected a Habsburg conspiracy. Since the Habsburgs and other European royals couldn't stand Napoleon I and certainly didn't want to recognise them as one of theirs, least of all let him marry a "real" princess,
Marie Louise's father might have asked her to make sure she got pregnant by another man (perhaps designated in advance and ready to accomplish his task) to make sure that the Bonaparte bloodline didn't "pollute" the noble Habsburg lineage. Isn't it strange that the Marie Louise's second husband, the
Count von Neipperg, who fathered her three other children, happened to be appointed at the Austrian embassy in Paris exactly from the time Marie Louise arrived in Paris to marry Napoleon ?
The Austrian embassy would have been a place where Marie Louise could have gone easily without Napoleon, and where the perfidious manoeuvre could have taken place, with the benediction of the Austrian emperor. Then, as good Catholics, the same man who fathered Napoleon II would have been forced to marry Marie Louise once Napoleon I was out of the picture. Note that Adam Albert von Neipperg
had curly blond hair, just like Napoleon II.