。
She went to Paris to see her aunt.
Literal
She [topic-は] aunt [to-に] meet purpose [with-で] Paris [to-へ] went.
目的で (for the purpose of) is a formal way to express the reason for a trip — more explicit than the common purpose に (verb stem + に + motion verb). あう (to meet) takes に to mark the person being met. The combination 叔母にあう目的でパリへ行った is slightly formal and written in tone; casual speech would more likely use 叔母に会いにパリへ行った.