Paris’ oldest standing church, the Romanesque St Germanus of the Fields, was built in the 11th century on the site of a 6th-century abbey and was the main place of worship in Paris until the arrival of Notre Dame. It's since been altered many times. The oldest part, Chapelle de St-Symphorien is to the right as you enter; St Germanus (496–576), the first bishop of Paris, is believed to be buried there.
An English brochure (€10) is available; proceeds go towards the current restoration works ongoing until 2020 (the church will stay open throughout). Free early-afternoon organ concerts are held on the last Sunday of the month; check the website's calendar for times. Other concerts take place on Thursdays and Fridays at 8.30pm; details including prices are listed online.