An American in Paris was, in many ways, the ultimate mixture of art and Hollywood musical. Made at the height of MGM's powers as a musical powerhouse, the film features memorable music from the Gershwins, who rightly have been called the 20th Century's equivalent of Beethoven and Mozart.
Gene Kelly was also at the height of his powers in this film, though it could be rightly argued that this movie was just the warm-up for his best work in Singin' in the Rain (1952). The two films are actually closely linked. Aside from the Arthur Freed connection, the Broadway Melody segment in "Rain" owes its existence to the incredible American in Paris Ballet sequence in this film. This might well have been the only time a dance number is specially mentioned in the opening credits of the film. And it deserved to be, as it showcases Gene Kelly's skills as a dancer and choreographer to their utmost degree.
The film's cast is uniformly excellent. Leslie Caron, incredibly making her film debut, shows a maturity that makes you think she'd been making films for years. Her introductory dance sequence, and later her work on the Ballet, provides some surprisingly sexy moments rivalled in MGM Musicals only by Cyd Charisse's work in Singin' in the Rain and The Band Wagon. Oscar Levant is hilarious as Kelly's stoic pal, who gets two of the film's best moments: during the end party sequence (which I will not give away for anyone who hasn't seen the film), and one of the film's most memorable musical numbers which couples his incredible piano skills with state-of-the-art (for the time) special effects.
Less memorable are Georges Guetary as Kelly's romantic rival, though he does get a few musical highlights, and Nina Foch as Leslie Caron's romantic rival. The May-December relationship between Kelly's character and Nina's reminded me of the same "kept man" relationship seen between George Peppard and Patricia Neal in Breakfast at Tiffany's.
There are a few elements of the film that made it less satisfying for me than Singin' in the Rain. The Ballet, though lavish and well-produced, doesn't really fit with the rest of the movie. Without giving away the plot, the Ballet just happens, with no real rhyme or reason. And unlike the Broadway Melody sequence, it really doesn't have anything to do with the plot -- and in the best musicals, the songs always have some sort of raison d'etre.
Making matters worse is the ending of the film which happens immediately after the Ballet. Although the ending shouldn't be a surprise (this IS an MGM musical, after all), I was hoping for a bit more ... movie after the Ballet ended. It's as if director Vincente Minnelli felt that he couldn't follow the Ballet with anything else. The film literally left me in the lurch.
That negative aside, An American in Paris rightly ranks alongside the best of Hollywood's musicals. It doesn't quite reach the heights of Singin' in the Rain, but it comes close and it remains a testament to Gene Kelly's skills as one of the greatest dancers of all time.

This movie is so awful, it is hard to find the right words to describe it!
At first the story is so ridiculous.A narrow-minded human can write a better plot! The actors are boring and untalented, perhaps they were compelled to play in this cheesy Film.
The camera receptions of the National Forest are the only good in this whole movie. I should feel ashame, because I paid for this lousy Picture.
Hopefully nobody makes a sequel or make a similar film with such a worse storyline :-)