On the flight route from Atlanta (ATL) to Paris (PAR) in only eight and half hours you will be within driving distance of the Eiffel Tower, Moulin Rouge and many a flamboyant French baker. In that flight time you will have covered 4 380 miles, on the direct flight that is. There are about 3 of those a day, offered by Air France and Delta.
A trip this far unfortunately disqualifies most of the low-cost airlines. But don't despair there are still ways to save money on your air ticket... the old-fashioned way, by booking far in advance and avoiding peak seasons.
Paris has a very efficient transport system so getting around will not be a problem. Keep in mind though, that Charles De Gaule Airport is a sprawling, exhaustingly large airport, so budget in a little bit of time just for getting around. To get to the city you can grab an RER tain, or a shuttle as well as buses or taxis.