The plot is formulaic and predictable for a romantic comedy, except with the interesting twist that this time the two leads have a purportedly 20-year age gap.
I will say that, perhaps because I don't understand Portuguese (I saw a Portuguese dub) and the subtitles weren't of good quality, the dialogue and situations didn't seem to be as bad as they would be in a typical US production. Although maybe that's just up to the novelty of it and it comes from a uniquely French tradition.
What really makes this a compelling film and worth watching, though, is the direction and performances of the two leads. The woman who plays Alice very skillfully conveys a career woman being assailed on all sides and practically shoved into having a relationship that someone in her position in real life would consider absurd, but then coming to develop ambivalent feelings toward the teenager she's forced to spend time with. Now, the romance isn't very well-developed - there's never really any reason for her to be attracted to Balthazar: neither fetish nor dashing confidence nor extreme attractiveness nor skill with women on his part. However, his female counterpart does look like someone whose emotions for the boy germinate despite her logical mind trying to pull away in the opposite direction. It's an internal battle conveyed in half-forced smiles and sighs of half-repressed frustration.
As for the Balthazar actor, he seems to be brimming with attraction and hope toward this older woman. At least on his side, it's a realistic portrayal - an attractive woman unexpectedly gives him the time of day and he does his best to please her, coming to grow attached in the process. It may have been the lighting, but the scene in the auditorium with his eyes twinkling as Alice crushes him slowly was powerful.
Highly enjoyable, to say the least.
Honourable Mentions: Down to You (2000). Boy falls in love with girl but girl wants to devote herself to fun and career. Another pretty decent story about a young man in love with an amivalent woman.