The Musee de Bretagne is located in the same building as Les Champs Libres and the library, right next to the Charles de Gaulle metro station. It's free on every first sunday of the month. They have a variety of historic displays, such as rocks, pottery, fashion, and items special to the region. I found my first visit to be rather boring, although it was helpful that most exhibits had english translations as well.
The library was much more interesting in my opinion, but if you're in Rennes on the first Sunday of the month and have absolutely nothing else to do, stopping by here may be an option. read more