"Une Aventure" features Ludivine Sagnier portraying Gabrielle, a single unwed mom who is the mistress to an older independent businessman/investor. Although Gabrielle is well provided for by her lover, with a nice modern apartment and a nanny/maid, and although she is the one character in the movie who does not have to work for a living (she calls herself a "lady of leisure"), she is depressed and slowly descending into the depths of mental illness. The main question, as the movie progresses, is whom she will pull into the depths with her (we see just how deep the depths are at the very beginning of the film, as the rest fills in the story leading up to the opening scene).
Gabrielle stumbles into Julien one night, who has just moved into her neighborhood, and that triggers a relationship that draws Julien into her life, with all its problems. Julien, although he is living with a woman, starts pursuing and trying to help Gabrielle both out of human kindness and because he is attracted to her. The circle expands as we get introduced to Julien's lover, Gabrielle's lover/provider, and the wife of Gabrielle's lover/provider. This being France, it is possible for all these people to know and interact with everyone else without furniture being thrown at each other. But that doesn't mean that there aren't tensions, or that there isn't hatred buried just beneath the surface of interactions, or that everyone is going to live happily ever after.
The best performance is turned in by Bruno Todeschini as Louis, Gabrielle's lover/provider. Ludivine Sagnier shows in this role that she is more than just a pretty face, and she does an adequate job portraying a character who is the opposite of upbeat and perky.
Those who purchase or rent "Une Aventure" hoping for a duplicate of Ludivine Sagnier's compelling performance in "Swimming Pool" are likely to be disappointed. Sagnier's character in "Swimming Pool" is carefree and often merrily unclothed; in "Une Aventure" her character is depressed and passive, especially during her romantic couplings. Although there are a few brief nude scenes, and Ludivine wears a very flattering dress in a nightclub scene (this is what is pictured on the box cover), there are nowhere near as many as in "Swimming Pool". Watch "Une Aventure" only if you are into dramatic French cinema about adult relationships.