Poitiers

Poitiers is a small city situated on the Clain river, to the south of Paris. While there isn't that much to do in the city itself, it does work well as a starting point for visiting other places in the region. 

Poitiers is easily reached from Paris, by either train or bus. Both transport terminals are located in the same building to the east of the city centre. Various local buses travel to/from the bus/train station to other parts of the city.

Poitiers by Bus

France is unusual, in that it doesn't really have any intercity bus services. As a result, there are no scheduled bus services between Paris and Poitiers, or any other French city for that matter. If you are travelling internationally however, Eurolines do operate services to/from Poitiers, so it may be worth checking with them to see if they have a route that suits you. 

There are plenty of local bus services in Poitiers, which are operated by Vitalis. A map of all the local stops, with route information can be found here.