While the question may never be answered definitively, it won't be for lack of trying. The BnF's version of the show was met with critical acclaim in Paris this spring. NYPL's Utopia will run in New York from October 14 to January 27, 2001.
Admission is free.
A citywide consortium of 17 cultural institutions is presenting a broad range of related events, and two books will be published, including an illustrated companion volume. I first proposed a joint exhibition to the BnF about five years ago. The challenge was to come up with a theme that was suitable to both libraries. It was the El Dorado' episode of Voltaire's Candide that inspired me to propose utopia as a topic. By happy coincidence, our French colleagues were also contemplating an exhibition on this theme.