I had planned to take the train from CDG to Lyon upon my arrival on Dec 4, however, I received an email from SNCF that my train would be cancelled due to a conductors strike. But, the communication also said: train traffic will be severely disrupted from Friday December 2 to Monday December 5, 2022 on long-distance trains, with 4 TGV and INTERCITES out of 10.
I informed Rail Europe and was promptly received a refund although I did not request it.
Do I take a chance that some trains will still run or try to arrange a more expensive and less green transport (i.e. a flight)?
If you could add that leg to your itinerary, that would be an option. Or, you could buy a ticket for Monday morning and stay the night in a hotel near the Gare de Lyon. There is also the threat of another strike December 7 if current negotiations aren’t productive.
"Some' trains will still run, indeed, but unfortunately on the South-East axis (which includes Paris-Lyon), SNCF projects it will run only about 1/3 of the trains it normally runs. (In other words, your line is worse than the national average of 40%).
I would be tempted to do as Bets says and get a train Monday morning, but only you can know how much flexibility you have (timing vs price etc)
Also please do yourself a favor and purchase directly from SNCF rather than Rail Europe.