Which Chopin piece has this melody?

[gn622]

In the coda of the polonaise fantasie op.61, there's a sad melody that  seems so familiar but i can't remember which other Chopin piece has it, it 11:40 till 11:48 in this video;

Perhaps im confused and its just too "chopinesque" that it sounds familiar  

by the way, i think that this is perhaps one of the greatest pieces ever composed for the piano.

[mjames]

That's just the "Polish" rhythm that's present in almost all of Chopin's work