Sainte-Chapelle.

The C.13th stained glass upper chapel is exquisite, with romantic classical concerts in the evenings. 4 blvd du Palais, 1st / M: Cité / 53 40 60 80 / Mar-Oct 9.30am-6pm, Nov-Feb 9am-5pm / closed daily 1-2pm / sainte-chapelle.monuments -nationaux.fr