The train station in Grenoble has a good TGV link from Paris, approx 3 hours.
There is a bus from the station, www.vfd.fr
Attention !! During winter season, reservation is obligatory: 33 (0)476 604 708 (Monday to friday, 9-12am / 2-5.30pm) or via the site juntil 7 jdays before the départure. Timetable LER 35: Grenoble-La Grave-Briançon
Or timetable Grenoble-Les 2 Alpes: get off at the Chambon dam stop, just before the climb to 2 Alpes Taxi de La Meije can come to collect you.