
See http://www.worldcat.org/title/fantaisie ... c/60625865 - referring to 3 libraries specifically (Newberry, Alcuin, and St Pancras (London).) It's definitely Worldcat*, not the member libraries (two of which member libraries have "18--", one of them the more accurate [1869]), -- that is inserting the [1885 or 1886] publication date information with the explanatory line here
"Publication date determined from information maintained at the IMSLP/Petrucci Music Library website."
It's not quite clear what information of ours Worldcat is using, though, given that the date is probably wrong. The (Paris: Schott) score was composed in 1866 (for the 50th anniversary of the 1816 re-establishment of the Academy of Arts and Sciences...) and published in 1869 or 1870 (from Hofmeisters Monatsbericht) at latest (plate 1312 Schott)...
I don't have an account yet on Worldcat, so really can't contact them as yet, I don't think (and is this really important enough to irritate them about? ... Maybe. OTOH, any publicity is good publicity. Maybe. Sort of.)
*Actually, not definitely, sorry, my mistake. The list of libraries you see in a Worldcat entry is incomplete; some libraries are "hidden"- the Free Library of Philadelphia doesn't show even if it's got something, for instance- but any information that its library catalog can contribute to the Worldcat entry will still show up there (instrumentation, etc.) It's possible that this is from, not Worldcat, but one of the increasing number of hidden libraries... (and no, don't know why. Seems that Library of Congress, and U. Rochester NY, may be among those one no longer sees in that list, or not for all their contents anyway...)