Its a spange to the Iron Cross.
"The holder of either class of the Iron Cross of The Great War who distinguishes himself will receive a silver clasp with an eagle (wings outspread) holding a wreath and swastika and the year 1939 which will be worn on the ribbon in the case of the Second Class and pinned above the Cross on the left breast in the case of the First Class."
You can see the top half of one on Rommels left pocket in this picture. He was awarded the Iron Cross 1st class in WWI. So the spange is worn directly above the second WWII Iron Cross 1st Class decoration.

The photo of your example shows what appears to be a reproduction. The proportions aren't correct. Originals were done in a silver wash, not sterling or silver plate. The example in the photo appears to be chromed with a gold background wash or plate.
Here's an original in fair shape, price around $145 US.

And your example. Looks like the plating has chipped in the top right hand corner of the "1939" framing ( the "gold" plate is showing ). Originals did not have a "gold" background.

Fasinating hobby, many books on the subject. I'm a few months in, lots to learn.
Fun stuff.