In 1861, the city authorities in Paris decided to build a church in the Chaussée-d'Antin quarter. The works were entrusted to Théodore Ballu, winner of the Grand Prix de Rome in 1841. Passionate about Gothic art, and a great admirer of the Renaissance, his personal interpretation for the Church of the Holy Trinity brought together Italian and French styles, combined with medieval elements.
For this building, designed to be the focal point of an urban complex in an affluent and fashionable area of Paris, the main feature was on a square tower, crowned with an octagonal bell tower, topped with a cupola and openwork lantern. This single tower on the façade would extend the view down the rue de la Chaussée-d'Antin.
The lateral façades comprised four bays separated by pillars, with two windows between each. Octagonal sacristies were added at each end and were joined to the choir, also octagonal, with small, cylindrical turrets. The sacristies were two storeys in height, and lit by two windows.
This large, beautiful drawing shows the draughtsmanship of the architect, who, as regards the tower, did not hesitate to correct a section he considered inaccurate or clumsy.