Forget about SatNav - it's just a toy for the gadget-concious - a Michelin map is far better. Buy the red 16 miles/inch and add a few of the yellow 6 miles/inch for areas of interest.
Generally stay off the Autoroutes and main N roads, the D roads being about the best for driving and scenic pleasure.
Anywaher in the French alps is good - try the roads N of Nice around the Italian border, or the passes, such as the Col de l'Iseran and Col de Lauteret, not to mention the Petit-St. Bernard into Italy. The list endless.
A good route south is the autoroute through Clermont-Ferrand towards Beziers - I travelled it last week by Z3 and it's a dream road - also toll-free.
What to see depends on your preferences, but a good selection is:
Aircraft & Space Museum at le Bourget airport - on the N19 in the N of Paris, but easy to find and lots of free parking. We stayed in Senlis and drove down in half an hour.
Churches - try the Eglise de Ste-Therese at Liseaux (Normandy) or the Little Eglise Ste-Foy in the World Heritage village of Conques (Auvergne)
Chateaux abound - Near Paris try Versialles (all day experience!) and Melun (as used in Moonraker). On the Loire there is Chenoncaux, Chinon, Chambord, and Azay-le-Rideau. Near Limoges is Hautfort.
Also near Limoges is Oradour-sur-Glane, the village destroyed by the SS in 1944, and now a monument.
I could go on for ever, but the best answer is to go and see.
I'll be at le Mans, camping in the lay-by Terre Rouge with a red Z3 - maybe see you there!