Improve the bracketed part of the sentence.
"When I (go) to Paris, I shall visit the Eiffel Tower."

In a conditional or time clause referring to the future (introduced by words like when, if, until, before, after), we use the Simple Present Tense to denote the future action, while the main clause uses the Simple Future Tense (shall/will + V1).
Structure: When+Simple Present,+Simple Future

Therefore, "When I go to Paris" is correct, and no improvement is required.