I like this simple flat frame because it looks like oak, but is in fact a gesso frame that has been painted to imitate oak wood. This seems strange because oak is relatively inexpensive, so to replicate it by hand painting the wood seems rather unnecessary, still a nice example a faux bois frame, and not the type of work that you see everyday.
The book 'Collecting Picture and Photo Frames' by Stuart Schneider has a few examples of faux bois frames, the author also has a very detailed website with numerous photos of antique frames, mostly American but a few European examples. A really interesting site, and some frames are also for sale:
