The Tilsitt was a 90-gun Ship of the line of the French Navy. She was the second ship in French service named in honour of the Treaties of Tilsit.
Started as Diadème, Tilsitt was transformed into a steam and sail ship of the line while still on keel. She took part in the Crimean War and in the French intervention in Mexico before becoming a prison hulk for prisoners of the Paris Commune.
From 1873, she replaced Fleurus as the hulk serving as headquarters to the French naval division of Indochina in Saigon.