Air France is in Skyteam and not *A
If you are flying economy and you want to keep the price on the low side, I would go with UA.
LH does not always give you 100% EQM so be careful when you book with them.
You could try Swiss air but check if you get full EQM.
The advantage of UA is that you get E+.
I personally fly continental because as a plat I usually end up getting an exit row for free or an easier upgrade.
Not sure if you are staying in Europe and for how long.
If you are just turning around and coming back the same day you arrive then CDG is easy because you do not have to clear customs or security.
There is also a nice lounge in CDG.