It's tight, but IMHO (begging the above posters' pardon for disagreeing a bit) not totally absurd. You should be in Paris about an hour and a half after you deplane. Get off the RER at St.-Michel Notre Dame. Walk through the cathedral, look at the Roman ruins excavated under the plaza in front of it, check out the gardens behind it with the deportation (Holocaust) memorial, walk over the short bridge from there to the Ile St.-Louis and get some Berthillon ice cream from the window opposite. Then get back on the train.

You'll have about an hour, but if you've never been to Paris before I'd go for it. An hour in Paris is not to be sneezed at.