There are high speed trains (TGV) between Paris-Montparnasse and Rennes every hour of the day and every half hour during peak periods. The trip takes 2 hrs 15 minutes.
From the station:
- by taxi: a 20 minute trip
- by metro and bus: from the station, take metro line A (a metro every five minutes during the day) towards "J.F. Kennedy". Get off at the "République" stop, then take bus C4 towards "Beaulieu Atalante" (a bus every eight minutes). Get off at the "Clos Courtel" stop. Walk towards the big broadcasting tower. Take the second street on the left (five to ten minutes' walk).