The best way to discover Brittany is by rental car. The easiest and quickest way for tourists to get to Brittany is through Nantes, which has its own International Airport and it also situated on a number of regular rail and TGV (high-speed) lines. You can reach Nantes from Paris, Marseille, Lyon and Lille. It is just over 2 hours by TGV from Paris. Trains run regularly throughout the day. There are also direct connections from Nantes to the Charles de Gaulle airport of Paris and to Lille if you would like to bypass Paris.
If you have already a car, Nantes is easily accessible by car from Paris by taking the A11.