I've had recent similar experiences at both airports. My transit thru CDG was not from UA to Thai, however. It was UA to LX. It was a MISERABLE connection because of long slow lines at immigration and security. I had maybe 5 minutes to spare, on a 1.5 hour connection, and the gates were very close together. No long walk involved, whatsoever.

FRA gates, on the other hand, are FAR FAR FAR apart. The good news is, since you are arriving and connecting to TG in F, you will be met at your arriving flight and escorted to your lounge/gate (NO golf carts). I agree that the lounge near gate B43 is very nice. Just spent time there a few days ago, waiting for the TG flight to BKK in F. Hubby spent an hour or so sleeping in their big sleeping room.

The TG agent who met us in FRA at the gate and escorted us was a little bit inept, but he did manage to collect a boarding pass for me, which UA at ORD could not give me when we checked in for the ORD to FRA flight in F. I was afraid UA had lost my F seat on TG when I couldn't get a boarding pass at check-in. I had some flight-switching last minute, and was afraid my reservation was all screwed up, but it worked out just fine.

I guess I would go with FRA as my choice, but the plane is showing wear. It rattles a lot at take-off! I was surprised to see it ageing so fast. We took this same flt BKK-FRA less than a year ago in F, and there was no rattling and shaking at take off. Oh well... I digress...

I'd probably choose FRA. I'm not sure if a TG agent at CDG could expedite a connection or not, the way the agent can cut lines at FRA.