A 2009 French psychological thriller originally titled "Ne te retourne pas." Jeanne, an author of biographies, begins noticing small changes in her life. First, the dining room table is facing a different direction. Then, pieces of furniture are replaced. Eventually, even the appearances of her husband, her children and herself become unrecognizable. Because of an accident, Jeanne has no memory from before she was eight, which her husband suspects is the cause. But, Jeanne believes something sinister is going on as every aspect of her life changes. Directed by Marina de Van and starring Sophie Marceau and Monica Belluci, this film is engaging and intriguing to the end.
Don't Look Back is a little confusing towards the end, but here's what I interpret the whole story to be (Massive, movie-killing spoilers ahead):
There are two families, a French one with an eight-year-old girl named Jeanne, and an Italian one with an eight-year-old girl named Rose Maria, and a boy named Gianni. Rose Maria's father resents her because she is not his child, so she is sent to live with the French family. The French family, including Rose Maria, are in a car accident which kills Jeanne and leave Rose Maria with no memory. After the accident, Rose Maria believes she is Jeanne, and the French mother does not try to convince her otherwise, but does not love her as much as her "real" child.
In adulthood, "Jeanne" has a husband and two children, and regularly sees her mother. But, she still has the Italian family and the original Jeanne floating around her mind, as it were, and replaces them with the people in her own life. Her husband becomes her Italian brother, her mother becomes her Italian mother, and she becomes the adult Jeanne would have been. These replacements are the people we see at the beginning of the film. The alterations, the changed people, are who they really are. This is why the original husband looks exactly like the adult Gianni, and why the dark-haired Rose Maria grows up to be the dark-haired Jeanne, and the first version of adult Jeanne has light hair, like the blonde child Jeanne. This is also why the last image we see of the family and apartment is the altered version - that's how things have always been, but now Jeanne can see it, too.