I'll avoid going too far into details about the film, but there is a scene where the two participants meet at an abandoned chateau and instead of my preconceived notion of what a pistol duel would look like, they disappear from one other's sight, and then proceed to stealthy find and kill the other individual that way.
The scene in question. This is essentially the last scene, so spoilers.
Was there a historical precedent for this kind of duel?
So... Yes. Maybe. The movie is fictionalization of an alleged series of actual duels. I say allegedly because what is true and what isn't is not exactly clear... The history of dueling is one quite prone to less than satisfactory verified anecdotes. But I wrote previously about this here.