hello gillykins
visit http://www.raileurope.co.uk dept. cdg 5/12 07:46, arr. 10:10 strasbourg
return 7/12, dept 12:10 arr cdg 14:37 or dept. 19:00 arr. cdg 21:28
the price for the return is £150 (expensive) for either train on the return leg on the 7th.
the only other option is flying from cdg - strasbourg. 4 departures on the 5th dec and 3 return flights on the 7th. as an example only dept cdg 5th 13:20 arr. strasbourg 14:25. return flight dept strasbourg 11:10 arr. cdg 12:20. the price inclusive of all taxes etc....... is £109.40. the other flight combination is approx. 10% more at the utmost.
just remember when you visit air france http://www.airfrance.co.uk change the country to france, then click on all stopovers - france - strasbourg. this will get you quotes on french internal flights.
regards
jim