If time remains, you may want to explore the medieval cobbled streets of the Vieux Quartier (Old Town). At the foot of the cathedral are lanes containing gabled houses and humped bridges spanning the Eure River. From the pont de Bouju, you can see the lofty spires in the background. Try to find rue Chantault, which boasts houses with colorful facades, one of which is 8 centuries old.
A highlight of your visit will be Musée des Beaux-Arts de Chartres, 29 Cloître Notre-Dame (tel. 02-37-36-41-39), next to the cathedral. A former Episcopal palace, the building at times competes with its exhibitions -- one part dates from the 15th century and encompasses a courtyard. This museum of fine arts boasts a collection covering the 16th to the 20th centuries, including the work of masters such as Zurbarán, Watteau, and Brósamer. Of particular interest is David Ténier's Le Concert. Open from May 3 to October 30 Wednesday to Monday from 10am to noon and 2 to 6pm (closed Sunday morning), the rest of the year, until 5pm. Admission is 3€ ($3.90) for adults, free for children.