Jeanne Baré joined the expedition disguised as a man, calling herself Jean Baré or Bonnefoy. She enlisted as valet and assistant to the expedition's naturalist, Philibert Commerçon, shortly before Bougainville's ships sailed from France. According to Bougainville's account, Baré was herself an expert botanist who cheerfully accompanied Commerçon on the most troublesome excursions over rugged terrain and had a reputation for courage and strength.
Incredibly, Baré's true gender remained undetected by the entire company of the expedition until they reached Tahiti. As soon as she and Commerçon landed on shore to botanize, Baré was immediately surrounded by Tahitians who cried out that she was a woman. It was necessary to return her to the ship to protect her from the excited Tahitians. From this point on, Bougainville noted dryly, "it was difficult to prevent the sailors from alarming her modesty".
Baré told Bougainville that she was 26 or 27 years old, an orphan, and had been born in Burgundy. She had taken to disguising her gender after the loss of a lawsuit had left her in financial distress. She had previously served as a valet to a gentleman in Paris, and had joined Bougainville's expedition because the prospect of a voyage around the world had "raised her curiosity". Bougainville wrote in his account of the expedition that she would be the first woman to have completed such a voyage.