"At Long Last Love" from the "Sinatra & Sextet: Live in Paris" 1962 concert album (album released in 1994)
I've been looking for this song performance for ages, ever since I watched Return to Me the second time. (The first time I was recovering from the emotional rollercoaster that movie takes you on.) The soundtrack doesn't have this song on it, played during one of my favorite scenes. (When everyone's dancing at the restaurant.)
I figured out which song it was, but every version I could find online sounded different from the one in the movie. And yes, I did actually have the movie going and compared the song tracks to the clips I could find online. No dice. He usually sings it much slower and smoother than the one that is in the movie. So, I gave up the search.
Until this weekend, when I was watching the movie again, and realized I could see part of the CD that the characters are holding when starting the music. Thank goodness for Pause! It's not a clear shot, but the cover definitely had a black center, with a white border. Definitely enough to match, thanks to the Internet! And I found it. I don't want the whole CD, so unless I find a single for sale somewhere, it'll just be in my reference file. But at least I know which version I'm looking for now.
Man, I love research.