Yep this one looks like it will be tough to get. Going to Paris at the end of the month for a week and I Searched award availability all week, with one night stays, and still nothing came up.
If I were you though I'd get the CC card (if you don't already have it) and chop up the stay in the 2 other paris hotels that are right by each other. That is what I plan on doing, along with using my 2 free nights at the Park Hyatt
