One week in Paris is adequate. We were there this May with our 2 year old.
So a week in Paris will get you to see the major sights, you could spend a year there and not see anything. The Eiffel Tower is a definite, as is Notre Dame (walk the whole way around the Cathedral), Sacre Couer is also a must, being able to see the entire city from a different perspective. The boat tours and hop on-off buses are also great especially to see the bulk of the city with little ones who may prefer to just sit and play.
Then there are the museums...try Musee D'Orsay as something different, but the Louvre is the one to go to. Don't expect to see everything though, just pick a few areas and see them comprehensively.
Provence is beautiful, there are plenty of B&B's and places to rent. Check out places like Aix-en-Provence and Cassis, we did this and skipped the major city of Marseilles and don't regret it (although I do hear it is a great trip).
Have a great time