The massive Romanesque bell tower may date back to the thirteenth century. The chancel occupied the ground floor before the construction of the nave from 1745 to 1748 and the present chancel which is now located on the opposite side.
The winged tabernacle with reliquaries is one of the most beautiful in Alsace. Produced in 1668, it comes from the altar of Lucelle Abbey.
At the rear, a large altarpiece painted by Jean-Jacques Bulffer (1744-1819) represents St. Leger, the patron saint of the parish, with the church of Koestlach lower left.
The side altars in Baroque style were made in 1751. The ceiling of the nave is decorated with a representation of the Assumption painted in 1747 by Joseph Xavier Hauwiller.
In the nave, on the right-hand wall, the two paintings on wood from the mid eighteenth century are attributed to Mathias Jehl.
Bench heads (1867) from the former Paravicin foundry in Lucelle. The organ is by Rinkenbach Valentin (1837). On the 1780 baptistery note the snake with the apple, symbol of original sin. Marc GLOTZ text. Sundgau By Bike
Rue des Romains, 68480 Koestlach