Starring Julie Delpy. In French, with English subtitles. Rated PG

Actor, writer, and director Julie Delpy has been around the movie block quite a few times. Her work with Ethan Hawke alone has revealed a canny surveyor of matters of the heart and other geographies. And she made strong impressions directing the delightfully Woody Allen–esque 2 Days in Paris. So it’s shocking to see Delpy come up with a comedy as amateurishly awful as Lolo.

Things start okay, with the director as Violette, a haughty Parisian designer on vacation in Biarritz with her even snarkier gal pal (Karin Viard). Violette is fretting, mainly due to her track record of frustratingly short affairs. Both are surprised when she meets and subsequently falls for local Jean-René, played by Dany Boon—massively popular in France, although his comic skills prove less than contagious. Here, he stays mostly straight as a semigeeky IT guy who moves to Paris for a new job and budding romance but remains a joke to Violette’s 19-year-old son, an up-and-coming artist nicknamed Lolo (mop-haired Vincent Lacoste).

In a bald-faced rip-off of the Amerindie Cyrus, which had stay-at-home Jonah Hill scaring suitors like John C. Reilly away from mommy Marisa Tomei, Lolo makes nice with J.R., while plotting his rapid departure. Unlike Cyrus’s Oedipal wrecks, however, Lolo’s schemes are downright stupid; they involve itching powder, poison, and physical assault. And he keeps an illustrated diary of his transgressions. Somehow, Mommy dearest never gets a whiff of her son’s increasingly dangerous psychosis. Hilarious, right?

The whole movie, in other words, could have been presented as a disturbing thriller. But that probably would have meant thinking a little harder about her characters and the truly weird implications of their actions. Delpy wasn’t prepared to do that, but—much like Violette—she didn’t know enough to walk away when something dear to her went toxic.