Where in the world?
The flag of Cameroon has three vertical stripes of green, red, and yellow with a yellow star in the center.

Cameroon

Population: 26,545,864

Region: Africa

Subregion: Middle Africa

Capital: Yaoundé

Top Level Domain: .cm

Currencies: Central African CFA franc

Border countries

The flag of the Central African Republic has four horizontal stripes of blue, white, green, and yellow with a red vertical stripe in the center and a yellow five-pointed star in the upper hoist-side corner.

Central African Republic

Population: 4,829,764

Region: Africa

Capital: Bangui
The flag of Chad has three vertical stripes of blue, yellow, and red.

Chad

Population: 16,425,859

Region: Africa

Capital: N'Djamena
The flag of the Congo has a green field with a yellow diagonal stripe from the lower hoist-side to the upper fly-side.

Congo

Population: 5,518,092

Region: Africa

Capital: Brazzaville
The flag of Equatorial Guinea has three horizontal stripes of green, white, and red with a blue triangle at the hoist side containing a white star.

Equatorial Guinea

Population: 1,402,985

Region: Africa

Capital: Malabo
The flag of Gabon has three horizontal stripes of green, yellow, and blue.

Gabon

Population: 2,225,728

Region: Africa

Capital: Libreville
The flag of Nigeria has three vertical stripes of green, white, and green.

Nigeria

Population: 206,139,587

Region: Africa

Capital: Abuja