Nocturne No.14 in F-sharp minor Op.48 No.2:

Composed in 1841, in dedication to lady Laure Duperré.

There are two things about the middle section :
1) it is in Db major
2) like the middle section of op.48 No.1, it is slower than the rest of the nocturne (molto piu lento), which is not the usual organization of a nocturne (slow-fast-slow)


http://piano-room.blogspot.com/2008/03/nocturne-no-14-in-f-sharp-minor-op-48.html