Its Gothic cathedral dominates a charming old town (vieille ville) of medieval and Renaissance houses on Rue Saint-Martin, Rue Saint-Malo, and Rue Bourbesneur.
The old town is very small. 
mnli hypothesis: The old town is very small.  premise: Its Gothic cathedral dominates a charming old town (vieille ville) of medieval and Renaissance houses on Rue Saint-Martin, Rue Saint-Malo, and Rue Bourbesneur.