What is the subject in Jules and Jim are visiting from Paris?

The question is a bit ambiguous. It's unclear what you're asking for. Are you asking:

* What is the subject of the story "Jules and Jim"? In this case, the subject is the complex love triangle between Jules, Jim, and Catherine, set against the backdrop of early 20th century Europe.

* Where are Jules and Jim visiting from? They are visiting from Paris, France, which is where the story is set.

Please clarify your question so I can give you a more accurate answer.