2000's Selon Matthieu (To Mathieu) is Breillat's most recent film that she's written but did not direct, and it's also her most recent film that's still not on DVD in English (excluding Une vieille maîtresse, which we trust is coming).
Breillat cowrote the story with Cédric Anger and director Xavier Beauvois, in which Benoît Magimel plays Matthieu, a factory worker who works with his father in Normandy, until his father is fired for smoking on the job. While Matthieu fights to get his job back for him, his father dies in a car crash. But Matthieu thinks it was a suicide and decides to exact revenge on his boss by having an affair with his wife (Nathalie Baye).
Selon Matthieu is available on DVD, but not with English subtitles. There's a nice, French DVD (R2, PAL) with an anamorphic, widescreen print. This is also available in France as a 2-disc set with another of Beauvois' films, Le Petit lieutenant - the Selon Matthieu disc is the same as the one that's sold seperately. There's a healthy number of extras included in the set, but they're all for the Le Petit lieutenant, not Selon Matthieu.
Oh, and there's an anamorphic, widescreen Spanish DVD, as well. It's Region 2 and PAL encoded, with optional Spanish subtitles and a Spanish dub. But, yeah. Nothing for us English speakers.