Holy Motors snuck into theaters this weekend, skipping the usual tread of press releases and press screenings. Critic Robert Ham deems it the best film of 2012.

Critic's Grade: A

The movie couldn't have come from a more unlikely source: Leos Carax, the visionary French director whose last feature Pola X was released in 1999 and landed with such a resounding commercial and critical thud that, until recently, no one would hire him. So with nothing more to lose, and the financial backing of a half-dozen production companies, Carax went for broke on Holy Motors, using nearly two hours of screen time to comment wryly and sharply on the state of film and the entertainment industry.

Carax himself appears onscreen at the beginning of the film, in a devilishly metaphorical dream sequence where he emerges into a theater filled with sleeping patrons. It quickly moves to the main story, which follows Mr. Oscar (the craggy and lithe Denis Lavant, in a bravura performance), a gent who drifts through Paris in the back of a limousine and adopts various guises along the way. He emerges from the auto as an old woman begging for change on a bridge, a distraught father of a teenage girl, a motion capture artist in a skintight bodysuit, and, in the most memorable sequence, as a mentally unstable homeless man who eats flowers and manages to kidnap Eva Mendes from a fashion shoot.

There's never any real explanation of what these "appointments" are all about, apart from one small exchange in the limo with an executive who feels that the shape-shifter has lost his passion for his work. In response, Oscar opines for the old days when you could see the cameras, adding that he continues this exhausting routine as part of "the beauty of the act."

It's telling that as I tried to parse out the purpose of Lavant's character in modern-day Paris, I kept returning to other filmic references. Could he be something like the kuroko, the black-clad stagehands who appear at moments in Masahiro Shinoda's 1969 masterwork Double Suicide to manipulate the action onscreen? Or is he more like the Strangers from Dark City, slipping in and out and affecting the world as part of some grand experiment?

Carax acknowledges throughout Holy Motors that his film is merely one brief stop in the long history of motion pictures. But by commenting on each era of the film industry—from its earliest experiments to modern CGI—and by using some of its reference points (look for the nod to the 1960 classic Eyes Without A Face at the end) the director urges viewers to remember how potent and indelible the art form can be. Walking away from Holy Motors, your head will swim with imagery—and with an insatiable desire for more just like it.