A gentleman is characterised by impeccable manners, charm, courtesy, and the avoidance of physical force or intimidation to steal, and often has inherited wealth. They steal not only to gain material wealth but also for the thrill of the act itself, which is often combined in fiction with correcting a moral wrong, selecting wealthy targets, or stealing only particularly rare or challenging objects. [wiki]
A. J. Raffles, Arsène Lupin, Simon Templar and others are well-known examples, but they are all fictional characters. In real life such a person does not exist, thieves are ordinary villains, without any moral or superior sense.