He's gone to Paris = He's in Paris now. For example: A: Is John in the office today? B: No, he isn't. He's gone to Paris for a conference. He's been to Paris = He went to Paris and then he came back. A: Can you recommend a good hotel in Paris? B: Sorry, I can't. Why don't you ask Tom? He's been to Paris lots of times. I hope that's clear.

Hi Igor, “Has gone to” means that someone is on the trip now. “He’s gone to Paris” - he has left and is on his way or maybe he is there now. But he is not *here*, now. The trip is in progress. “Has been to” is a statement about completed trips in someone’s life experience. “He has been to Paris” —> maybe he studied abroad there while he was in college (and he is now middle aged), or maybe he went on a trip there some years ago, or whatever the case is. But he is not on a trip to Paris *now*. His trip or trips are in the past, as completed actions.

I. He's gone to Paris. - He is currently in Paris, having left here, or wherever he was previously. II. He's been to Paris. - He once went to Paris, and could be anywhere now. He has visited Paris, at least once in his life.