Lannion seems to fit the bill for a perfect mediaeval French village as half-timbered jetting houses are in abundance.
The city is on a hill with meandering roads where lots of adorable modern shops occupy old time buildings, making you feel as if you've stepped back in time.
On top of that, there is a lovely tree surrounded park, complete with old stairs that go to nowhere, celtic crosses, and an old out of use church building. I wouldn't have been surprised to discover a fairy circle there.
The city is small and do-able in a day, but what it lacks in size it makes up for in charm.