Jeunet is, for once, operating outside his usual "comfort zone" and that's not a bad thing at all. While I have come to love him for his unique style, quirky colours, sharp textures and character actors caught by fisheye lenses, sometimes it pays to do something a little more restricted. As a comparison, Lynch's "Straight Story" comes to mind - a director known for decidedly non-mainstream sensibilities shoots a "simple" road movie. And since "The Straight Story" is my favourite Lynch film, that's no small praise! Of course, there's some of Jeunet's trademark whimsical, playful optics on screen, but they never become mere gimmicks but always enhance the storytelling. And some - or probably all - of the most impactful scenes are really simple shots - no gimmicks, no gags, just faces and landscapes. While Jeunet's last, "Micmacs", lost itself a bit among all the optical fireworks and gags, this film here keeps it straight and focused and I liked it only the better for it. Also, the pace is much slower than usual (again, very like "The Straight Story") - most scenes are longer than strictly necessary, giving them time to settle in.
The weakest point may be the actors - the children are not as good as those in "City of lost Children", and most of the grown-ups are a bit one-dimensional. The nice exception being Helena Bonham-Carter who delivers a really fine performance, nuanced like you wouldn't have thought she still had it in her after all the hammed-up roles from the last years.
Overall, probably my second-favourite Jeunet film (have seen it only once at the moment, maybe I'll have to rewrite it a bit after more viewings), highly recommended - and I really hope he does some more "mainstream" projects like this where his playfulness doesn't drown the story!