I have read the book and just finished the series.
I might be the only person in the world who thinks this but I did not really care for the book. I love to read WW2 stories and this book took me months to read because it was incredibly boring. The story itself is beautiful but written so slowly.
That being said I felt the show had wonderful acting despite the fact the actors were not French / German or even sound it. The details of the story were vague at points and I feel like you would only understand some of them if you read the book. The show focused to much on the big picture and missed the details of the book which made it great (again not a huge fan of the book but still had great moments in it).
They could have made it a million times better if it had been spread out over a minimum of ten episodes.
If you absolutely love the book you will not care for the show, however as most people know they can only pull so much from a book in the time constraints and whatnot.
Worth a watch in my opinion. Definitely not as slow as the book but not as detailed either.