Notre-Dame de la Seds, Catholic church in Ville des Tours, Aix-en-Provence, France.

Notre-Dame de la Seds is a Romano-Byzantine church rebuilt in 1853 by the Aix architect Henri Révoil. Its pale beige facade rises from a grey stone base to a small stone bell tower holding a single dark bell; below a framed inscription panel sits a tall arched window with a dark infill. Three striped-stone arched doorways open at ground level, the wider central one with a carved tympanum and red double doors.

The original building dates to the 4th century when it served as the metropolitan church of the region. It underwent major reconstruction in 1853 under architect Henri Révoil, creating the structure visible today.

The name "Seds" comes from the Provençal for "seat", recalling its former rank as cathedral. On 8 December 1857 Archbishop Chalandon crowned a statue of the Virgin and Child here, drawing a crowd too large for the building, and the Marian devotion he established continues. Until October 1383 the relics of Saint Mitre lay in the apse; their transfer to Saint-Sauveur met resistance from the parishioners.

The church is accessible during services and regular religious activities throughout the week. Visitors should be respectful of ceremonies and keep in mind that access may vary depending on the day and time of scheduled services.

Beneath the church lies an ancient Roman theatre that was discovered in 2004 after remaining buried since the 5th century. This archaeological layer makes the ground below an unusual link between early centuries and today.