Marc-Joseph Marion du Fresne
In 1769, after Louis Bougainville's triumphant return to France, another French expedition set out for the Pacific. After hearing a rumour that an Englishman had found Terra Australis, the fifth continent and a land of wealth, Jean-Francois-Marie de Surville left Pondicherry, a French settlement in India, in the "S. Jean-Baptiste", but failed to make any significant discoveries.
Marc-Joseph Marion du Fresne sailed from France on the Mascurin in 1771 with the intention of returning Ahu-toru, the Tahitian whom Bougainville had taken to France in 1769. However during Ahu-toru's stay on Mauritius he contracted smallpox and died three weeks out to sea. du Fresne decided to return to the Cape of Good Hope for provisions and then continue on search of the Great Southern Land with his ship the Mascurin and the warship Marquis de Castries.
On 22 January, 1772 he discovered the Arid Islands, later to be renamed the Crozet Islands, after du Fresne's second-in-command, Julien Crozet, and on 3 March he sighted Van Diemen's Land. They followed Abel Tasman's route and anchored in what they believed to be Fredrick Henry Bay. However, the coastline at the time had not been fully explored and it is now believed to be Blackmans Bay where they anchored, went ashore and claimed Van Diemen's Land for France.
The act of possession took place on 5 March 1772, 14 days before fellow Frenchman St Allouarn took possession of a part of mainland Australia whilst at Shark Bay on the Western Australian coast. Marion du Fresne's party were the first Frenchmen to make contact with the Tasmanian Aborigines and the first Europeans to set foot there since Tasman. Du Fresne sailed on to New Zealand where he and some crewmen were killed by Maori warriors. The survivors retreated to Mauritius.
Marion Bay, to the north of Dunalley, Tasmania, was named after du Fresne by fellow Frenchman Louis de Freycinet on 17th February 1802, believing the bay to be where Marion du Fresne claimed Van Diemen's Land for France. Du Fresne in fact went ashore in Abel Tasman's Fredrick Henry Bay, a little further south, which today is known as Blackman Bay. This Blackman Bay is different to Bkackmans Bay, near Kingston, Tasmania. Confused? So was Tobias Furneaux when he explored this coast two years after du Fresne. He mistook what is today known as Blackman Bay for Frederick Henry Bay.
Furneaux's charts were used to prepare the Admiralty charts of today, which is why the name still applies to the wrong bay. It was at today's Blackman Bay that Tasman's ship's carpenter, Peter Jacobsen, volunteered to swim ashore with a pole on which was the Prince's flag, which he planted on the shore of the bay, on 3rd December 1642, the same bay where du Fresne claimed it for France 130 years later. This bay (near Dunalley) is not to be confused with Blackmans Bay, a suburb of Hobart on the D'Entrecasteaux Channel.
Terre Napoleon; a History of French Explorations and Projects in Australia by Scott
The Discovery of New Zealand: Marc-Joseph Marion du Fresne