This movie is based on the book of the same name in English. It is, of course, originally a French book (see the wiki here) and the movie Arthur et les Minimoys did very well in France.
I would recommend the book highly (I love characters like the Bogomatassalai and the imagination in Beta’s knife, for instance) but I don’t think much of the movie. It was light and somewhat fun but since I was the only one in the family who had read the book it made little sense to and had hardly any impact on them. Too much stuff was packed in and the characters weren’t well developed as they were lovingly done in the book.
Luc Besson, Director and Author, is supposed to have a sequel coming out. I would certainly read the book but I’ll definitely wait for the movie.