It is hard to discern a clear theme out of Bresson's "Pickpocket". The main character Michel is a thief, plain and simple. So little else is shown about the character. He seems devoid of emotion unless it is the thrill of stealing. His dealings with women and his mother seem distant and forced. Pickpocketing becomes his career and life at the very beginning of the film. Michel steals things, practices stealing things, and likely sits in his room thinking about stealing in the meantime.
Pickpocketing is a relatively minor crime, but Michel is never portrayed feeling any kind of guilt or conscience about what he steals. He hints at the idea that he is above the law, or "a superman". This is apparently the way that he escapes any kind of self-scrutiny, is with his 'superman theory'. The only thing that Michel expresses regret for is his careless attempted theft that landed him in jail. He even mentions making it as hard as he can for the police that have imprisoned him. If being imprisoned really bothers Michel he does little to show it in way of emotion. In fact, there seems to be little difference between Michel sitting in his room or his prison cell.
The thing that changes most for Michel, in prison, is his relationship with Jeanne. The scene where Michel is visited by Jeanne in prison is very awkward, and both characters seem to be more resigned to fate than anything else. Michel is oddly kissing Jeanne's forehead while she is slightly clinging to him. To me, it is unclear why Jeanne would have any interest in Michel, as he portrays no positive aspects other than providing her with some money at one point in the film. He seems so impersonal that as a viewer of the film, I cannot imagine him involved in any type of romance or attraction in his character.