St. Ludwig, Parish church in Saarlouis, Germany

St. Ludwig is a Catholic parish church on the Großer Markt in Saarlouis. Its neo-Gothic tower front, built by Vincenz Statz in 1883–1885, has a central tower with a clock and octagonal spire, flanked by two shorter towers. The nave behind it is a concrete Brutalist structure by Gottfried Böhm. Inside, a gilded altarpiece with pinnacles stands against a grey concrete wall.

The parish was founded in 1685, and the first Baroque church was built from 1685 to 1687 on the orders of Louis XIV. Its foundation stone was laid on 2 June 1685 by governor Thomas de Choisy. After structural problems, a neo-Gothic nave was built on the old foundations in 1865–1866. A fire during the city's 200th anniversary in 1880 destroyed the Baroque tower facade, which Vincenz Statz replaced with a neo-Gothic one in 1883–1885. Gottfried Böhm's concrete nave followed in the 20th century.

St. Ludwig is dedicated to Saint Louis IX of France, the patron after whom the city of Saarlouis was named. The dedication ties the church directly to the French origin of the city and remains visible in the name itself.

The church sits in the center of Saarlouis, within walking distance of the main square, making it easy to visit as part of a walk through the city. It is best to visit outside of service times if you want to look around the interior without interruption.

The 1970s nave was designed by Gottfried Boehm, a German architect who went on to receive the Pritzker Prize in 1986, the highest international award in architecture. He remains one of only a handful of German architects ever to have won it.