The Austerlitz was a late 100-gun ship of the line of the French Navy. Laid down as Ajax, she was renamed Austerlitz on 28 November 1839, still on keel. In 1850, her rigging was changed for that of a 90-gun, and a steam engine was installed. She took part in operations in the Black Sea in 1854. From 1871, she was used as a prison hulk of prisoners of the Paris Commune. Between 1874 and 1894, she was used as a school ship. She was eventually broken up in 1895.