Located in the centre of the old town near the waterfront of Toulon, construction on the Cathedral, known as the Cathedral Notre-Dame-de-la-Seds, started in 1096 on the orders of Gilbert de Boson, Count of Provence to offer thanks to the Virgin for his safe return from the Crusades. Built on the site of a former church which was on the site since the 5th century, the cathedral took 700 years to build and consists of a mixture of styles including Romanesque, Gothic and Classical.
For a period in 1543–1544 the cathedral was transformed into a mosque in order to cater for the 30,000 sailors of the Ottoman-Barbary fleet who at the time were allies of France.
As a result of the development of naval base and port of Toulon in the 17th century, the cathedral underwent a number of enlargements and between 1654 and 1659 the original Romanesque building was enclosed, incorporating the Chapel of Relics. Its orientation also changed, so that the main doorway was relocated from the west to the south. Due to the restructuring, a distinctive feature is the unequal width of the aisles. The interior contains three naves of varying lengths with pointed arches
Between the years of 1696 to 1701, the classical façade was installed. This was damaged during the War of the Spanish Succession in 1707, when cannonballs hit the building. The statues on the pediment were destroyed during the French Revolution (1789-99) but the façade was restored in 1816. The façade contains a number of memorial plaques dating back to 1239 and 1234.
Between 1737 and 1740 the clock tower standing 36 metres high was constructed. The bells were removed and melted down during the Revolution but were replaced with the current four bells in 1806/7.
The interior of the cathedral with its simple Gothic ribbed vault ceiling contains a number of chapels and a selection of wooden gilded statues and frescos and a number of 17th and 18th-century paintings together with a walnut pulpit. The original stained-glass windows were destroyed during World War II and were subsequently replaced. The organ dates from the 19th century. In 1961 a new altar was installed in the main apse which incorporates built-in bas-relief from the old altar.
The 18th century Baroque retable, (the altarpiece.) incorporating sculptures/paintings is located in the Corpus Christi Chapel and was constructed to hold the Holy Sacrament. This is a copy of the original one and was made of marble and stucco in 1681 to replace the original wooden one which was destroyed by fire in 1661.