The Sarah of Sarah’s Key is not star Kristin Scott Thomas—who is very good here—but rather Mélusine Mayance, a young French actress seen in flashbacks. Or maybe Scott Thomas is in flash-forwards. And that, in a nutshell, is the problem. Sarah is one of thousands of French Jews arrested and sent off to concentration camps for extermination during the Holocaust—and French authorities are responsible for helping Hitler with this atrocity. We come upon this horrible bit of history through the research of Julia (Thomas), an American journalist living in Paris. For some reason, scenes of family drama between Julia and her husband are offered as a counterpoint to the Holocaust. That’s just bad planning. Everything about the contemporary subplot in Sarah’s Key feels tacked on—and tacky by comparison.