The movie opened today - 29 July 2015 - here in France, and I saw the second show here where I live, the small town of Paimpol. There were perhaps 30 people altogether in attendance. I could hear that the few children among them were bored. So, first comment: 1) This is not a movie for small children. It won't interest them.
2) If you are expecting a video reproduction of St Exupéry's story, you will be very disappointed. It's in this movie, but it only comprises a small part of it. Most of the movie is a frame for that tale, the story of a small girl who meets an elderly aviator who tells her, in bits and pieces, the story of his encounter, many years before, with the Little Prince. If you go expecting just what you know from St Exupéry's story, most of this movie will therefore be an annoyance to you.
It took me awhile to accept the frame story. It's fairly banal, fairly Hollywood. Nowhere near the originality of St. Exupéry's remarkable tale. But if you let yourself go with it, it has an appeal over time.
The part devoted to St. Exupéry's original tale is the best, as far as I'm concerned.
We also see the prince as an adult, very changed. That came as a shock at first to me, but again, I let myself go with it, and it had a certain fairly obvious interest.
This is not a great movie. "Ernest and Célestine" is a thousand times better. But it's worth seeing.
Again, however, this is NOT a movie for little children. They will be bored.