The quote to which you refer does not appear in the text of Ernest Hemingway's, "A Moveable Feast." The quote appears in a "Forward" written by Ernest Hemingway's son, Patrick, and published by Scribner in a number of editions after the manuscript was originally published in 1964.
The editions in which Patrick Hemingway's "Forward" appears is the original manuscript as Ernest Hemingway prepared it to be published. It appears that the "Forward" was written during the late 1960s.
In Patrick Hemingway's "Forward," he asks, "What can I say about the title?" He writes that "Mary Hemingway derives it [the title] from a remark made by her husband to Aaron Hotchner: 'If you are lucky enough to have lived in Paris as a young man, then wherever you go for the rest of your life, it stays with you, for Paris is a moveable feast.'"
The edition available to me and from which my answer to your good question is derived is a paperback reprint from 2010: Hemingway, Patrick. Forward. "A Moveable Feast: The Restored Edition." Ernest Hemingway. Scribner: New York, 2010. xii. Print.
NOTE: I should add that some editions published from the late 1960s to date, do not include Patrick Hemingway's "Forward"; however, the following text, unattributed, is found in Front Matter and/or on the Back Cover: "'If you are lucky enough to have lived in Paris as a young man, then wherever you go for the rest of your life, it stays with you, for Paris is a moveable feast.' --- Ernest Hemingway, to a friend, 1950."
Thank you for a good question.