Enclaves of Forcados and Badjibo
The enclaves of Forcados and Badjibo were two territories close to the river Niger, in modern Nigeria, leased to France by the United Kingdom under the Anglo-French Convention of 1898. They were obtained by France after several expeditions along the Niger, by Hourst (1894), Granderye (1898–99), Toutée (1895 and 1899-1900), and Lenfant (1901–02, etc.).
Source: Wikipedia — Enclaves of Forcados and Badjibo (CC BY-SA 4.0)