Les Merovingiens d'Aquitaine

So, I have this habit of buying old books in foreign languages, preferably in French, which is my second language. I picked this up in a little used book shop in Yuma, AZ about eight years ago. It's part of a larger collection from the Foreign Office Library. I think it has been rebound. It has a lettering guide stamped on the spine, which reads O 2682. It was printed in the mid to late 1800's, I'm pretty sure. I have no idea what the value is. I don't know if it is even worth anything by itself. Any information would be great!