This movie is available to be watched for free on Youtube. They show the final part of the film "Les Annees Terribles" dealing with the violence of the Revolution including the storming of the Bastille, the March of the Women into Versailles and the imprisonment and execution of Louis the 14th and Marie Antoinette. Marie is played by actress Jane Seymour and her guillotined death is tastefully shown. We see her being led to the guillotine via the tumbril, the crowds on the square and the guillotine. But when the blade comes down, they cut to a little girl with a toy of the guillotine executing a doll of Marie to let us know that this is what really happened to Marie. Most movies about the death of Marie Antoinette never show anything graphic or explicit at any rate.

Marie-Antoinette is shown being executed, but not directly. The camera pans out to a little girl in the crowd simulating the execution with a toy guillotine and puppets of Samson and Marie-Antoinette, with the puppet's head falling as the crowd cheers after the real blade chops her head off-camera.
Corday is just shown stabbing Marat, nothing more.

Yes, the scene of Marie-Antoinette being guillotined was shown in the movie, but not in an explicit way though. I don't think Charlotte Corday's guillotine scene was shown. The movie just showed the court condemning to death if I remember correctly.

I can't remember exactly if Corday's and the Queen's execution were shown. I do remember Robespierre being executed at the very end of the movie.