Overseas flights from CDG departing from 2F.
 

I keep hearing that some flights to destinations outside Europe will leave from CDG terminal 2F in the next months. (This is from Air France employees themselves) This is rather odd, as that terminal normally only handles intra Schengen flights, and there are no passport control points there. Also I believe that terminal can't handle widebody planes.
So what is going on?

Lot of confusion here. As you said 2F is entirely Schengen and there is no plan to change that. What exist for years is that some non-Schengen flights have their check-in ops done in 2F. Then you pass security in 2F and you turn right and follow the way to 2E-L or M and you pass passport control on the way. The list of flights concerned vary from one season to another. This concerns of course only passengers departing from Paris and not pax in transit in CDG.

There is no walk back. You will depart from the L concourse in 2E so the distance will be exactly the same. And I recommend you to go to 2F as 2E can be a total zoo (in the sense hyper crowded) in the morning. The only difference I could mention is that from 2F, you walk to 2E-L (approx 200-300m) while from main 2E you take the automated train to reach L. So if you don't have disabilities/troubles to walk, definitely go to 2F.