Île Fanac, River island in Joinville-le-Pont, France.

Île Fanac is a narrow river island in the Marne at Joinville-le-Pont, about 3.9 hectares, with a vertical retaining wall along the water, a strip of grass and low shrubs, and a dense canopy of trees. Near the left end a tall slender tree rises above the rest, and behind the foliage stand white walls and steep dark roofs with pointed spires. The island holds around forty buildings and is car-free.

Long used for agriculture, the island was partly built up from the late 19th century, alongside the facing Quai de la Marne. A ministerial decree of 3 September 1965 classified part of the site as picturesque under the law of 2 May 1930. In 2022 the classification was extended to the whole island, up from 85 percent.

The municipal art school operates from a former restaurant building that once caught the attention of celebrated authors. This space shows how the island evolved into a center for artistic activity along the river.

The island is accessible to pedestrians via stairs and an elevator from Joinville Bridge. Visitors should park on the mainland side and expect to reach the site entirely on foot.

The island's shoreline shrank by several meters during the 1900s due to river floods and boat traffic. The concrete reinforcement of the opposite bank worsened this erosion process considerably.