Warning: May (definitely) contain spoilers.
I have seen a handful of French films over the years and cannot recall a single one that is not in its own particular way depressing. In each of these films there has always been a subtle (or not so subtle) message that seemed to say “people are bastards and life is a bitch, but that's just how it is”. The Secret for me was no exception to this pseudo-rule. Of course being that it strongly relates to the Holocaust the fact that it is depressing and sends a message like that is somewhat understandable.
Although the film was well constructed and well acted for the most part it lacked much in the way of originality. The characters existed on an individual level and were clearly three dimensional, however the overlying plot was boring. It was, with just a few bare exceptions, another film in which a child discovers the sad secrets of his parents and the parents or other related authority figures are revealed to be flawed people who happen to have extra-marital relationships. A French film that depicts cheating as not really that bad? A real shocker there.
Frankly many of the characters are frustratingly unsympathetic. While they do have moments or aspects that should make us feel for them there are so many things that ruin it. The father in particular is a huge bastard, and yet the way the movie ends it almost seems like we are supposed to accept that he is truly repentant and sad over the past because what? He is distraught when the memories rush back after his dog dies (this is what we are lead to believe is the case anyways) and his cheating and desires end up being okay because his wife and son (not that he knew at the time) were already dead when he cheated? The fact that he was distant from his second son because he wasn't 'physically strong' and the fact that he leaves his second wife (despite the situation in which they came together) because she is paralyzed...both of these aspects are glossed over with the latter only being of enough importance to casually mention at the very end.
His first wife gets herself and her son captured and killed because she can't bear the thought of seeing her husband making moon eyes at her brother's wife? The entire family keeps a first wife, a dead uncle, a dead brother, and even the fact that they are Holocaust survivors and Jews from the second son...and this is okay? The movie is titled The Secret and yet we don't really get a chance to see or understand how the second son, our 'protagonist' if you will, has taken all of this information and adapted to it as an adult. In fact, the only interesting aspect of the protagonist's 'adult self' and the segments involving him (brief though they are) as that they are shown in black and white while the past is shown in color. This seems to say that the present is less real than the past, but regardless of this message the parts pertaining to the adult protagonist seem extraneous.
Underlying all of what we are presented is the knowledge that the later parts of the 'secret' being told are occurring during the Holocaust, specifically the German occupation of France. Except for two relatively brief scenes the tension over the father's rejection of Judaism to save himself is largely ignored. It is almost a non-issue. For me personally the film might only qualify as a 'Jewish' film on the same level that Schindler's List is a Jewish film. It happens to be about Jews and the Holocaust. Beyond this it is just another tale of shallow love, shallow betrayal, the Holocaust, family secrets, and human beings generally being bastards to other human beings for little to no reason.