I sort of had the similar question about bag drop. We will be using something called TGVAir from Poitiers (SW France) to CDG then on to Hong Kong the check-in will be at the Poitiers TGV terminal for both the TGV POI-CDG and CX CDG-HKG sectors but bag drop is obviously not available at Poitiers and has to be done at the airport. Because of other train connections (to Poitiers) we will arrive at CDG at 13:35 for the flight at 20:30 so if bag drop is only available when check-in opens 4 hours pre-flight then we have a 3 hour wait with heavy luggage. We were hoping that maybe that the ability to bag drop might be available earlier.