I am loathe to say this as I rather enjoyed having a proxy version of my favourite (London) past time - watching people. However, this is a misconceived, ill-constructed film which makes a palindromic attempt to inflate a document of urban life whilst deconstructing a (half-baked) thriller.
The film is three acted (three 'nights'). In the first a man watches girls. In the second he follows one. In the third he watches them again, although there's a suggestion that he may have acted on what he's learnt from the first two. The film's merits are largely to do with the unimpeachably youthful beauty of the principals, although Michaël Balerdi, the young man, is a distractingly weak actor. As I mentioned I also liked the nicely photographed corners of Strasbourg and the drama inherent in the smattering of tracking shots...
... alas, these tracking shots are mucky, inconsistently rendered (an un-steadycam?). The continuity errors are glaring. I was also easily off-put by boom mic intrusion and imperfections on the print, as well as hopelessly rendered foley sound (really bad!).
The worst thing - and this is no one's fault - is that once the 'pursuit' gets going, the film immediately looks like the opening sequence of Michael Haneke's Caché. If you even begin to compare these similarly themed films Guerin's piece begins to look very clumsy indeed. 3/10