While facing unplanned roadtrip around France, ordering "Discover France" was a good solution to decide on places we want to see on the way (it has many pictures!), gives great highlights of towns if you're only there for few hours, gives travel recommendations regarding small villages to visit. I also found very useful 2-5 days roadtrip around region recommendations. And when it describes sightseeing recommendations - it gives working hours and addresses.
However its not detailed enough for actual travel. Places mentioned in the guide are not mentioned or not easy to find on regional maps provided (so not clear how to get to them), maps are not detailed enough, some interesting places or big cities are not mentioned at all in the book, so when you stumble upon them while driving - the book gives you no information at all about what's there to do. "Eating & Sleeping" recommendations are only 2-3 per big city, that are only most famous/expensive ones.
Overall - I definitely missed a full Lonely Planet "France" additionally to "Discover France" - to take full advantage of the travel. However if you're not at all bothered about seeing everything and you're not travelling by car - this book might be just enough.