"Un éléphant ca trompe énormément" is the original of the American remake "The woman in red" (1984, Gene Wilder). Not always are American remakes good films, but if not they still can lead the way to films that are good. See for example "Insomonia" (2002, Christopher Nolan) pointing to the 1997 original by Erik Skjoldbjærg or "Nightwatch" (1997, Ole Bornedal) pointing to the Danish 1994 original "Nattevagten" by the same director. The 2002 "Insomnia" incidentatlly wasn't a bad film at all, the 1997 "Nightwatch" was.
"Un éléphant ...." is about four men in mid life crisis. It shares this theme with for example a film like "American beauty" (1999, Sam Mendes). Films about mid life crises are almost always bittersweet. They have comical elements, as men pursuing a new love interest after all those years invariably behave strangly. On the other hand they are also sad because in essence these men are dissatisfied with their lives.
"Un éléphant ..." is no exception. With respect to the sad element, none of the four men is really happy. One is an incurable womanizer who panics every time his wife leaves him, one is a single still dominated by his mother, one is a homosexual who has not come out yet and the main character is a civil servant with a dull life.
We can see the comical element throughout the whole movie, sometimes bordering on slapstick. Not all jokes are funny, but some are. The slapstick in the scenes with horses are in my opinion very funny. I could imagine these scenes have been an inspiration for director Benedikt Erlingsson when making "Of horses and men" (2013).
Last but not least, "Un éléphant ... " (and also "The woman in red") derive their fame to no small extent from a film quote derived from "The seven year itch" (1955, Billy Wilder) showing the billowing dress of Marilyn Monroe ("The seven year itch"), Anny Duperey ("Un éléphant ... ") and Kelly LeBrock ("The woman in red").