Sarah's Key, 111 mins, 12A

Sometimes, two films about meteor strikes or Robin Hood go into production at once, but it's still strange to watch Sarah's Key only two months after The Round Up. Both are concerned with 16 and 17 July 1942, when 13,000 Jews were marched from their homes in Paris by the French police, and some scenes are so similar that they could be swapped from one film to the other without anyone batting an eyelid. But while The Round Up was content to inform us of these events, Sarah's Key uses them as the starting point of a much more ambitious, far-reaching story. At first the film's strength, ultimately it's the opposite.

One of its two heroines is a 10-year-old girl called Sarah (Mélusine Mayance) who locks her brother in a cupboard in the family home when the police come knocking. The trick works, and the boy isn't found, but Sarah soon realises that if she doesn't escape from her captors her brother will starve to death. Now, is it just me, or is that a bit sick? Aren't the historical facts dreadful enough without a phoney race against time?

Then there's a present-day strand about an American magazine journalist (Kristin Scott Thomas) who's researching an article on the round up when she discovers that her apartment in Paris has been in her husband's family since August 1942. Were her in-laws collaborators? How much did they know about their home's previous occupants? Scott Thomas's steely performance gives the film some dignity, but as she flits from Paris to New York to Florence (how many magazines would have the budget for that, these days?), we hear more and more about her husband and her unexpected pregnancy and less and less about the round up. The really striking thing about the Holocaust, according to Sarah's Key, is how ambivalent it makes an American reporter feel about her marriage, 70 years later.