Murder by Death is a 1976 satirical comedy that looked at several different fictional detectives and their story telling style, such as hidden twists, unrevealed clues, and similar machinations. Each of the detectives (or group) was based on "real life" fictional characters.
Sidney Wang - Based on Charlie Chan created by Earl Biggers
Sam Diamond - Based on Sam Spade, from Dashiell Hammet's Maltese Falcon
Dick and Dora Charleston - Based on Nick and Nora Charles, also courtesy of Dashiell Hammet via the Thin Man films.
And, as you have pointed out, Miss Marbles and Monsieur Perrier are based on Miss Marple and Hercule Poirot via Agatha Christie.
It also is a little bit of trivia that the main protagonist in the film is played by Truman Capote, himself an accomplished author, in one of his very infrequent film appearances.
Group shot of all the detectives at dinner. Truman Capote is under the hat in the foreground, and it includes supporting members such as Wang's son, Perrier's manservent, etc.