Cameroon has formally taken full sovereignty of the oil-rich Bakassi peninsula, ceded by Nigeria in 2008. The territory was handed over after an International Court of Justice ruling, ending years of border skirmishes.
The five-year UN-backed transition period exempted residents in the area, many of them Nigerian fishermen, from paying tax. Now the Nigerians must also apply for a residence permit or take up Cameroonian citizenship if they wish to remain.
Read further on BBC website.