The first reviewer is none other than my good friend Leon,so you can trust him when it comes to French/Belgian cinema:he knows what he is talking about.
This is a variation on a subject which has often be treated: someone rises from the dead and has to cope with the world of the living ,but it is given a rather original treatment ,if not always successful.
The film begins a bit like a modern fairytale and continues as a fantasy story,fortunately devoid of those special effects which mar so many films of this kind.The part of the mother is underwritten,and the first sequences focus on the man/child Relationship:to him,he's like a wizard ,who can make his wishes come true ,and he can in a way ,from the lonely snowflake which precedes the return of the father to the lovely pictures of snow falling down on Paris.
The movie becomes too talky when the two men meet ,and amnesia is always the easy way out.But further acquaintance shows this: a physical presence does not bring you one of your dear departed back;incidentally the key is given by Pierre Richard as the old Jew from Warsaw: a person is not only flesh and blood,it's also a lot of memories ,like those the Jews of the WW2 ghetto used to bury in the ground ;and even if he can bring a dead back,the hero is forced to give him his own memories he had buried in his mind after the loss of his wife.And all the padlocks of the Pont Des Arts would not be enough to keep those gone happy hours from emerging again.