Paris CDG Connection Time Terminal 1 to TGV

You can potentially make it if you walk fast enough and if your luggage doesn't take ages to be delivered...

Your flight will probably be on time as you are flying with Lufthansa. But since this is the end of the day, there might be a bit of traffic jam to get to the parking for the plane. Then, let's pick 10 minutes for this.

Then 20 minutes to get to the baggage claim and pick up your luggage (this is a bit conservative, it could be only 15 minutes).

So we are now at 30 minutes and you still have 39 minutes to get to Terminal 2 TGV station via CDGVAL. This shouldn't be an issue assuming it just takes 10-15 minutes usually.

You won't need to go through a Passport control as you are flying within Schengen area...

I think it's pretty tight, and you likely won't make it. Consider this time plan:

• 20 minutes from arrival to gate to getting your luggage (this is the minimum ever FWIW).
• 5 minutes walking to a TAXI stand.
• 5 minutes explaining the TAXI driver that you really want to go "around the corner" -- tell him/have written: Allez à la gare TGV de l'aeroport, s'il vous plaît. Or: Allez au terminal 2C, s'il vous plaît. (The second option is probably safer/better.) Be ready for some raised eyebrows as such a request is quite unusual.
• 10 minutes driving time. Have change ready. Expect price in the range EUR 10--17 approximately.
• 5 minutes running from the ground to the railway station. You get in at any of the terminals 2C, 2D, 2E, 2F, find the signs "GARE TGV" or "PARIS BY TRAIN", run, take 2 floors down by moving stairs, then find the entrance to the TGV station (check platform number), it's another floor down.
• 2 minutes -- that's how long in advance you have to be at the train. Note that you can enter into any coach within the same part of the train (the parts are coaches 1--8 and coaches 11--18, but very likely your train will be 1--8 only so you can enter anywhere).

Altogether: 47 minutes, and I'm being very optimistic.

I doubt any other option is faster. There's the underground train shuttle inside the airport (free of charge), but it takes 4 stops to go from T1 to T2, and at T2 you have to get up 2 floors and down 3 floors again, which also takes some time.

Note that the train starts in Lille, which means it could be slightly delayed, but (unfortunately for you), it's usually not the case.

I hate answers which say "Instead of what you're asking about, what about this?" but instead of what you're asking about, what about this?

I was extremely surprised to see there is indeed a train FranfortAM -> Poitiers.

(NOTE HOWEVER that, tragically, you have to shuffle stations in Paris: it appears that 53 minutes IS PROBABLY NOT ENOUGH TIME REALISTICALLY to make that connection across town.)