
First of all, I have to say four days are not enough to feel Paris' soul.I will tell you the best plan even four days are not enough. I bet you will say while leaving like this: "I wish I could stay one more day" :)
Day 1
Notre Dame
Saint Chapalle
Conciergerie
Square du Vert-Galant
St. Eustache
Bourse du Commerce
Center George Pompidou
Challiot Palace
Eiffel Tower
Hotel Des Invalides
Day 2
Versailles...