French President Francois Hollande has visited the ancient abbey Mont-Saint-Michel to inaugurate the bridge meant to ensure the site's island status, finalizing 10 years of construction.

The former causeway that used to link the world-famous abbey to the mainland has been replaced by a bridge that allows water to move freely around the monument and helps remove the sand infill in the bay.

This makes the monument an island at high tide and a peninsula at low tide.

The UNESCO world heritage site attracts over 2.5 million visitors every year.

Hollande said on Saturday that "man has repaired what he had damaged ... Nature regained its rights."

Visitors now use a car park on the mainland and travel to Mont-Saint-Michel on foot or by using a shuttle service.