Depends on the airport. Some airports support the ITI concept. The ITI (international to international) concept is where you're flying an itinerary that starts outside the US, connects in the US, and ends outside the US. In that case, your bag will be transferred to your second flight without you having to take it through customs. The passenger, of course, still has to go through customs and immigration. For that to work, you need two things:

1. You have to be going through a US airport that supports ITI--only a limited number do.
2. Your airline has to tag your bag correctly at the origination--they put a special tag on your bag so the baggage handlers in the US know it's an ITI transfer.

That's how it works. I have no idea whether ATL is an airport that supports ITI, and if it is, whether the AF agents at PTP will know how to do it.