Église Saint-Vincent de Carcassonne, Gothic church in Carcassonne, France

Église Saint-Vincent de Carcassonne is a Languedoc Gothic church in the Saint-Louis bastide, with a single nave 20.15 m wide, six chapels on the north side and seven on the south, and a nine-sided apse flanked by two seven-sided apsidioles. Its square-based bell tower rises 54 m in two phases, square for the first two levels (dated 1327) and octagonal above.

The first church of Saint-Vincent, north of the Cité, was demolished in 1240 during Raimond II Trencavel's failed attempt to retake Carcassonne. Seven years later Louis IX founded a new grid-plan town on the left bank, and in 1308 Philip IV authorised the purchase of four houses so the parish church could be rebuilt. Work began with the west porch and nave in the 1320s, contrary to custom, and the choir was finished only at the end of the 14th century.

The parish takes its name from the original Saint-Vincent church north of the Cité, destroyed in 1240; the present building was laid out in the new grid-plan bourg founded by Louis IX. In 1794 the Revolution turned it into a foundry casting artillery carriages, with seven double forges set in the chapels and two in the apse; it was returned to worship on 26 August 1795. In 1905 parishioners and curé Abbé Peyre blocked the state inventory; the door was broken open with an axe, and pieces of it were later mounted as a memorial panel.

The interior is accessible and allows visitors to view the artwork and stained glass closely. A steep staircase inside the bell tower offers those who climb it a wide view of the city and surrounding area.

The 54-metre bell tower, reached by 232 steps, was used as a geodesic point in 1798 by Pierre Méchain and Jean-Baptiste Joseph Delambre to measure the length of the Earth's meridian. Cassini and his sons also used the tower for their map of France. Its lower two storeys are square, with the year 1327 carved in the second room, while the upper levels are octagonal.