During the early 1600s, Île Saint-Louis was untouched and without any inhabitants. It was only when homes started cropping up on the island that a parish was established, with its first chapel emerging in 1623.
As more people settled on the island, there arose a need for a more spacious place of worship. The responsibility of designing this church fell upon François Le Vau (1613-1636), the lesser-known sibling and colleague of the renowned royal architect Louis Le Vau, who had crafted spaces for iconic sites such as the Palace of Versailles, Louvre, and Institut de France. Interestingly, this church became the sole architectural masterpiece François undertook without his brother's collaboration. The structure boasted the French Baroque aesthetics characteristic of the 17th century.
The foundation stone was laid on 1 October 1664 by the Archbishop of Paris. However, a series of hurdles, including financial constraints, hampered its progress. The untimely death of the lead architect brought about a change of hands in its design, with Gabriel Le Duc taking over, followed by two subsequent architects. In a twist of fate, a violent storm in 1701 ravaged the freshly built roof. As the years went on without much headway, houses started cropping up adjacent to the church, leading to modifications in the initially planned western façade. The church's doors were finally thrown open on 14 July 1726, a good six decades after its inception. Nature's wrath wasn't done though, as a tempest in 1740 laid waste to the original bell tower. In its place rose a lattice-designed tower, cleverly crafted to allow the island's fierce winds to flow through. A peculiar aspect of this tower was the clock, conspicuously hanging over the street, reminiscent of a storefront sign.
The tumultuous times of the French Revolution saw the church being shut, its adornments ripped apart, and its structure converted into a book storage. Thankfully, the purchaser reverted it back to its original ecclesiastical function in 1805, with Pope Pius VII consecrating the premises with a mass on 10 March 1805, during his visit to Paris to crown Napoleon as Emperor.
In 1817, the Parisian authorities acquired the building. Subsequently, an extensive rejuvenation drive was spearheaded by Abbot Louis-Auguste Bossuet, the Parish's head from 1864 to 1888. By trading the church's expansive library, he sourced funds that infused the church with shimmering gildings, murals, ornate stucco sculptures, and the vibrant windows admired today.
The church's entrance is marked by a clock hanging on the tower's side. Two angels, their arms wide, cradling the French coat of arms, adorn the portal. This artwork pays homage to the church's patron saint, King Louis VII, also known as Saint Louis. While the angels remain, the French Revolution left its mark by shattering the coat of arms.
Despite its vastness, the church's interior exudes intimacy due to its abundant gilded decorations and intricate details. Jean-Baptiste de Champaigne (1631-1681) lent his artistic vision to its ornate design, reflecting the opulent French Baroque style from the 17th century. Rounded arches in the arcades are complemented by pilasters featuring trompe-l'oeil designs, paired with travertine stone columns crowned with Corinthian capitals. These columns are further embellished with sculpted leaves and angelic figures. The interior is replete with carved scepters, symbols of justice, and various royal insignias, emphasizing its connection to King Louis IX.
The outer aisles of the nave are adorned with a sequence of chapels, each showcasing exquisite paintings and sculptures.
In the Chapel of the Communion, one can witness Charles Coypel's (1694-1752) masterpiece, "The Pilgrims of Emmaeus." This piece vividly captures a Eucharistic celebration, bustling with characters and movement.
The Chapel of the Compassion features a trio of paintings by the renowned 19th-century French romanticist, Karl-Henri Lehmann (1814-1882). These are "The Annunciation", "The Virgin Presenting Christ to the World", and "The Virgin and the Saints at the Foot of the Cross". Notably, his "Virgin and the Saints" piece was showcased at the 1848 Paris Salon.
In the Chapel of Baptism, visitors are greeted by eight petite paintings embedded in the wooden panels. These depict various episodes from Christ's life and are believed to be the work of early 16th-century artists. Accompanying these is Jacques Stella's (1596-1657) "The Baptism of Christ", a piece reminiscent of the Italian Renaissance artistry.
Lastly, the Chapel of Saint Mary Magdalene houses a monument dedicated to the 19th-century abbot Bossuet, a significant patron of the church.
The original 17th-century organ has long vanished. It was supplanted in 1744 by a Lesclop creation, distinguished by its intricate buffet adorned with rocaille carvings. Regrettably, this and many other Parisian organs of its time were dismantled during the French Revolution to reclaim the lead from the pipes for ammunition production.
The 19th century saw the installation of a modest Merklin organ on the tribune, though its quality left much to be desired. By 1923, this was substituted with a Charles Mutin organ, which incorporated the previous instrument's buffet. Sadly, this too was subpar and suffered from neglect. The 1960s witnessed another addition—a smaller organ in the choir, which functioned as the church's main organ for numerous years.
Fast forward to 2005, Bernard Aubertin crafted the current organ, financed by the City of Paris. Reflecting the German or Bach style, this modern organ boasts fifty-one stops. Notably, while it's a contemporary piece, it retains the authentic tower sculpture and carved angels from the 18th-century buffet.