Fiction by Jo Jo Moyes.
The story begins in German-occupied France during World War One (Yes I mean WWI. I thought it would be WWII as well, but it wasn't. I guess France just kept on getting occupied.) and jumps ahead to present-day Britain.
The two times are linked by one compelling piece of artwork, a portrait called "The Girl You Left Behind," and the two women who have the painting hanging in their homes.
It's awesome. Read it.
Also by this author: Me Before You