Frontier line dividing France from the County of Nice until 1860, this bridge bears the name of the principal craftsman of the annexation, Napoleon III. In 1845 a wooden bridge was built with a sentry box in the middle for the sentinels from Piedmont; it was replaced by a stone and masonry bridge between 1862 and 1864. In the summer of 1919 the aviator Auguste Maïcon flighted under this bridge several times. In 1923 the bridge was widened and a railway line was added. In 2010, the bridge was renovated for the 150th anniversary of the annexation.