This itinerary is heavily inspired by Rick's 3 weeks France itinerary, tailored to fit in 12 days. Please review and give me your feedback.
We'll be arriving to Paris from another EU town (likely Vienna), so in terms of jetlag, we should be fine.
Day 1: Fly into Paris, pick up rental car, and visit Giverny en route to Bayeux
Sleep in: Bayeux
Day 2: Spend day touring D-Day sights: Arromanches, American Cemetery, and Pointe du Hoc — and Utah Beach Landing Museum.
In late afternoon, drive to Mont St-Michel and visit its abbey
(I am worried this is too much in one day - let me know).
Sleep in: Mont St-Michel
Day 3: Head for Loire. Tour Chambord, then settle in Amboise and take self-guided town walk
Sleep in: Amboise
Day 4: Day trip to Chenonceau and Cheverny or Chaumont
Sleep in: Amboise
Day 5: Return the rental car (need to look into this). Train to Paris, Visit Eiffel tower
Sleep in: Paris
Day 6: Louvre Museum, (Optional) Orsay Museum, Notre-dame Church
Sleep in: Paris
Day 7: Montmartre, Sacre Coeur, Arc de Triomphe, Champs-Elysees
Sleep in: Paris
Day 8: Palace of Versailles, Gardens, Latin Quarter
Sleep in: Paris
Day 9: Day trip to Colmar (please let me know if this is possible) Or more time in Paris
Sleep in: Paris
Day 10: Train to Nice
Sleep in: Nice
Day 11: Villefranche-sur-Mer OR Eze OR Monaco
Sleep in: Nice
Day 12: All day in Nice
Sleep in: Nice