Hi Carol,
Saint Malo is a very nice town, but there is no squat, nor alternative places in town, as far as I know. Not far from there, anyway, in the same region (Bretagne) there is a forest that have been squatted to avoid its destruction: they have be evicted once, but they squatted again and they are still resisting... it could be a very interesting place for you to go. It's called ZAD of Notre-Dame-Des-Landes, and this is a link to a d.i.y. documentary they made about the Zone:
http://archive.org/details/ZadNddlQuandLesArbresSagitentWhenTheTreesShake
In the same regoin, there is also a brand new squat (near Brest) of anarcho-sailors: the house is facing the sea and they have a dry dock, so that the squatters can also repare/build sailing boats. At least this is their project, but they squatted one month ago and they don't know how long it will last... I'll give you the address if they are still there in june...