Bresson takes his title seriously. The movie does such a good job of showing how a pickpocket works that it was banned in Finland for several years for being too detailed in the presentation of the pickpocket.
The titular character, Michel (Martin La Salle), lives in one of the most beatdown rooms you'll ever see. Sparse doesn't get it. There's a ratty bed that takes up most of the space, a closet, and ... well, he keeps money hidden in a baseboard. The room is one of many examples of how Paul Schrader, who loved the film with a passion, imbued Travis Bickle with the loner status of Michel (Schrader wrote the screenplay for Taxi Driver). Michel has no friends ... even the pickpockets he works with as a team are unknown to him outside of their particular shared skills. He doesn't like to visit his dying mother. There is a suggestion that he will develop a relationship with young Jeanne (Marika Green), but for most of the brief 75-minute running time, a suggestion is all we get. (Fave trivia item: Green, then 16 and making her first movie, later became Eva Green's aunt.)
Bresson is an acquired taste, and Pickpocket is a fine place to start, not only because it's a good example of his work, but also because of that 75-minute running time. Of the ones I've seen, I'm partial to A Man Escaped, but Pickpocket is almost as good. The non-actors fit well into the style of the film. Pierre Leymarie, who plays Jacques, went on to become a professor ... this was his only movie. La Salle and Green continued acting for a long time ... among other credits, Green was in the softcore film Emmanuelle. #81 on the They Shoot Pictures, Don't They list of the top 1000 films of all time.