How to get to Rennes ?
Rennes can be easily reached by fast train from Paris in 1 hour and 25 minutes (~ 20 trains per day). Consequently, Rennes is conveniently accessible by train from any European city that has a possible connection with Paris. You can use the chronotrain website to find out which cities are connected to Rennes in less than 5 hours by train.
By plane or plane + train
Rennes airport offers direct flights from the 3 hubs of Paris CDG, Amsterdam Schiphol and Frankfurt. This makes it easy to reach Rennes from most oversea flights. Note that Paris CDG airport has a train station where you can directly reach Rennes by fast train in ~2 hours and 30 minutes (~ 8 trains per day). Amsterdam is also connected to Paris by train using Thalys, and London is connected to Paris by Eurostar trains.
How to get from Rennes train station to downtown Rennes by public transport?
The train station of Rennes is at the south of the city center and is connected to the metro lines making everywhere downtown accessible in 3 minutes.
How to get from Rennes airport to downtown Rennes by public transport?
The city center of Rennes is reachable in about 30 minutes by public transport by taking the line C6.