5 hour layover in Paris

The answer is no. It takes around 45 minutes to get to the Eiffel Tower from CDG and then 45 minutes back and then you usually have to be at CDG 3 hours before flights to the US. So that is 4.5 of your hours and we have not even touched on the time to exit the airplane and the secured area. Where are you traveling on to? Will your bags be checked through to your final destination?

if coming from the states it will take at least 2 hours to be out of the airport (through immigration and customs) and into town -- buying the RER ticket and getting there. Cabs are subject to traffic delays and risky. It will take another hour to get back to the airport and you need to be in the security line 2-3 hours ahead of departure. The minimum time for a quicky trip into town is 7 hours; the stakes of missing an onward flight are very high and stuff happens. (I have been on trams that broke down on the way to the station, trains that came in 5 hours late for a 3.5 hour trip, a London tube train that sat in the dark for half an hour underground when I was on the way to catch the Gatwick express to the airport and been in traffic jams because of accidents where I didn't move for an hour --- it doesn't always happen but it can so you can't cut it fine on a thing like this)