This is an interesting question, because so much of this story's power comes from the detached point of view of the narrator, who nevertheless seems to empathize with Paul. I think one place you could look for irony, however, is in Cather's treatment of the theme of deceit or truth. On one level, of course, Paul is deceitful -- he lies to his family all the time, and eventually becomes a thief. But for Paul, these lies are simply a means to a higher truth, which is his place in a world "of shiny, glistening surfaces and basking ease." For Paul, standing transfixed in the rain before the grand hotel, watching from the outside but living, in his imagination, on the inside, his imagined life of splendor is more than a fantasy. It is like an alternate reality that somehow has been cruelly denied him. His fugitive trip to New York, where he pretends that he is the son of wealthy parents, is less an escape from reality than a flight into reality. Cather, who is a truly great writer, sums it all up in a single remark: "He was entirely rid of his nervous misgivings, of his forced aggressiveness, of the imperative desire to show himself different from his surroundings. He felt now that his surroundings explained him." For Paul, the lie is the truth.