Upvote:0
Certainly no. The laws cannot be applied back in time. There was no legal notion of prisoner of war at the time of Napoleon. The corresponding international legislation was not introduced until the end of 19th century.
And even by this legislation he would not quality. Much later (in the middle of 20th century) a "war criminal" was defined. Perhaps he would qualify for "planning and performing a war of aggression". But this was more than a century after Napoleon's times.
Upvote:11
In the book Napoleon After Waterloo: England and the St. Helena Decision By Michael John Thornton the status of Napoleon is discussed in great detail, including questions of law.
There are several considerations:
On 13 July 1815, Napoleon wrote to HRH, the Prince Regent:
Napoleon's letter seeking hospitality from the British
The Prince Regent declined to offer hospitality in Britain, so he was summarily transported to St. Helena, a distant and isolated island in the south Atlantic, to stay for the remainder of his days.
Note added thanks to the research of @user8654. A few months later an act was passed "for the more effectually detaining in custody Napoleon Buonaparte", an ex-post facto law intended to regularize Napoleon's indefinite detention at the pleasure of the British government. In this act it states that he is to be treated as a prisoner of war, this despite the fact that all prisoners captured during the wars have already been released.
This act regularized Napoleon's indefinite detention.
Prisoners and Detainees in War discusses the evolution of the legal theory of prisoners taken during war; it has evolved considerably since the days of the French Revolution and the Napoleonic wars; one should not expect that the legal status of "Prisoner of War" could even be determined for a ruler who had abdicated