The story as related at several sites indicates that rather than being ignorant provincials, the residents had a very good, and somewhat clever(?), reason for hanging the monkey as a Frenchman.

The ship was wrecked and had been abandoned by the crew. Under the laws of the time, it was thus "salvage" (flotsam vs jetsam vs captured enemy stuff comes into interpreting the rules). If found without any crew on board, it was "the property of the Queen/King."

As the only "person" on board, it was quite necessary that the monkey be "found in court" to be a "French crewman," and hanged as an enemy, making the ship "a captured vessel" which could be kept, with whatever salvageable contents it contained, by the town.

There appear, from some sources, to be records affirming that this really did happen. Since even with a "lawfully convened court acting according to law" the action was a little on the shady side of the hill, it is understandable that the records might be a bit obtuse - so some still question the details.

In its full detail, the elements of "common folk who screwed the Queen" combined with "ridiculing the French" as looking/being like monkeys, does make it a tale begging to be contrived by a clever songster. Take your own pick on believing it all.

John