Following the start of the Sino-French War in August 1884, Nielly was mobilized to strengthen the French Far East Squadron under Amédée Courbet.

In January 1885, Courbet took a group of ships, including Nielly, to search for elements of the Chinese Nanyang Fleet, which were reported to be steaming to attack the blockade force.

After the war ended later that year, Nielly shifted to the Indian Ocean, where she was present for the final stage of the First Madagascar expedition, which secured a protectorate over the island.

The four ships of the Lapérouse class were ordered under the auspices of the naval plan of 1872, which was laid out to modernize the French Navy in the aftermath of the Franco-Prussian War of 1870–1871.

The navy sought new unprotected cruisers that carried a heavier armament than earlier vessels, while maintaining a similar size to keep costs from increasing during a period of limited naval budgets.

By then, the Far East Squadron, commanded by Rear Admiral Amédée Courbet, that time, also included the ironclad warships La Galissonnière (the flagship) and Triomphante, the unprotected cruisers Duguay-Trouin, Villars, D'Estaing, Volta, Rigault de Genouilly, and Champlain, and the gunboat Lutin.

[8] In January 1885, Courbet received word that elements of the Chinese Nanyang Fleet under Admiral Wu Ankang had sortied and were steaming south to try to break the blockade of Formosa.

Accordingly, he assembled a force that included Nielly, the ironclads Bayard and Triomphante, the cruiser Éclaireur, and the gunboat Aspic, along with a supporting transport.

Courbet initially believed the Chinese squadron would attempt to reach Fuzhou via the Min river and sought to block their path on 6 February.

Wu's squadron consisted of the unprotected cruisers Kai Chi, Nan Chen, and Nan Shui, the steam frigate Yuyuen, and the sloop Teng Ching; he had initially sought battle with the French, but upon realizing the superiority of Courbet's squadron, Wu decided to detach the slower Yuyuen and Teng Ching to seek shelter in Shipu, while his faster cruisers fled south.

Courbet ordered his ships to steam at least 13 knots (24 km/h; 15 mph) to try to catch Wu's cruisers, but Triomphante and Aspic could not keep this speed and so he sent them to blockade Yuyuen and Teng Ching in Shipu.

Courbet continued his pursuit of Wu with Nielly, Éclaireur, and Bayard, but he soon realized that he could not catch the Chinese ships, which were capable of 14 to 15 knots (26 to 28 km/h; 16 to 17 mph), and so he rejoined the rest of his squadron at Shipu at around 13:00.

With the knowledge gained, he sent a pair of launches armed with spar torpedoes on the night of 14–15 February to attack the two Chinese vessels, sinking them both.

[11] In March, the French commander, Courbet sent Nielly, Lapérouse, Champlain, Rigault de Genouilly, and the gunboat Vipère to blockade the mouth of the Yangtze river on mainland China.

The French blockade effort, which included other ports, proved to be effective at interrupting the movement of rice crops from southern China north.

[12] With the conflict over, the French began dispersing the warships that had gathered in East Asia; Nielly was transferred to the Indian Ocean division.