Back to France this summer. Ten days, fly into Paris (2nd time there). We've been to Provence and Normany previously. What do you think about 4 days in Paris and then TGV to Tours and rent a car and 4 or 5 days in Loire Valley? Finally, back to Paris and depart; any suggestions?
I would start the trip by flying into Paris, then travelling directly to Tours for the Loire part of your trip. Then finish with your time in Paris - that way, you won't have to transfer to three hotels.
Love Paris, Love the Loire... that will be a wonderful trip. But consider also adding Burgundy... easy to include with the Loire and a wonderful area to visit.
Lexma's suggestion to leave Paris for the end of your trip is good. If you decide that 4-5 days in the Loire is too long, Susan's suggestion of Burgundy is a great way to spend extra time.