Upon using French flour for the first time, you will notice differences in how the dough feels, how it rolls, how much water is required in recipes, and even how much butter or other fats are necessary.  French flour is fundamentally different from what you are used to.  It retains its natural fats, as they are not stripped during the milling process.  Also, French flour is lower in gluten, meaning it will have a less rubbery sheen to it, it will trap leaving gasses less readily, and a numerous other characteristics will be slightly different.  It will take a few tries before you get the hang of this new substance, but your taste buds will thank you for it.  Crepes are probably the easiest application that most effectively demonstrates the difference in results.