My Uncle Benjamin is a period comedy-drama set in 18th century France, directed by Édouard Molinaro. The film is based on a novel by Claude Tillier.
The protagonist of the movie is Benjamin Rathery (Jacques Brel), a young doctor who is known for his unconventional ways and free-spirited attitude. He lives in a small French village and is in love with Manette (Claude Jade), the beautiful daughter of the local innkeeper. However, Manette has no intention of marrying Benjamin until she sees a marriage contract.
Meanwhile, Benjamin's sister Bettine (Bernadette Lafont) is trying to set him up with Arabelle (Julia Dancourt), the daughter of old Dr. Minxit (Paul Frankeur). Benjamin agrees to meet Arabelle, but he is more interested in spending time with Manette.
One night, while Bettine is away, Benjamin and Manette are caught together by her father, who arrests her for indecency. Benjamin decides to go with Manette to help her, but their plans are foiled when they encounter the fat Marquis (Jacques Villeret), who humiliates Benjamin with a practical joke.
Determined to get revenge, Benjamin enlists the help of the Vicomte Hector de Pont-Cassé (Michel Serrault), a wealthy and well-connected aristocrat who is also attracted to Manette. Meanwhile, Manette has her own problems with her father, who wants her to marry a rich farmer.
With the help of Hector, Benjamin manages to get back at the Marquis and win Manette's heart. However, his actions have consequences, and he is eventually arrested by the Marquis. In the end, Benjamin is released and reunited with Manette, and they ride off into the sunset together.