The French film they watch in the movie is "Des hommes et des dieux" (English title: "Of Gods and Men"). In the book, the film they watch is "Jean de Florette", though its title is never stated.

I believe the title is referring to Louisa before Will's presence in her life. The sequel to the book is titled "After You".

I also didn't understand the title. Maybe the movie started directly on them meeting and the movie spent more time showing her before the job?

Many years late to your question…I loved the movie and just read the first book. When Will tells Lou he is still going to go through with his plan, she is heartbroken because she has done everything she can to change his life for the better and change his mind. She says “but that was before me.” Understandably, she feels like a failure and that all of her efforts were a waste if he still doesn’t want to live. After he is gone, Will reveals his thoughts to her and the things he has set in motion for her…and she realizes that of course she did have a big impact on his life, she changed his heart…but more importantly HE changed her life.

At this point, Louisa as well as the reader/viewer realize that this is not Will’s story…it’s hers. Me Before You.

When I saw that the author of the book wrote two books after this, I can understand how Will might have felt a little. I’m not going to be there, but the knowledge that Lou can go on to live a full life is satisfying. While suicide can be seen as selfish, that point of view is pretty generous of him. He cared more about her than he did anyone in his life before! And her living a good life made him feel at peace.