Nigeria was on Tuesday ordered to pay nearly $70 000 in damages after at least one person was killed and 12 seriously injured during the military's forced eviction of a slum five years ago.
The case relates to an incident on October 12, 2009, when families in the the southern city of Port Harcourt were forced out of their make-shift homes by the military.
The 40 waterfront settlements in Port Harcourt are thought to be home to more than 200 000 people and tens of thousands have been forcibly evicted in recent years.
It is still not clear exactly how many people died in the shootings in the area called Bundu Ama as there was no government inquiry.
But the Community Court of Justice of the Economic Community of West African States (Ecowas) ruled there was no justification for the shootings and said Nigeria's government had breached its obligation to protect the right to peaceful assembly.
Amnesty International's Africa director, Netsanet Belay, described the ruling as “remarkable” and paid tribute to the community's courage for standing up for themselves.
“It sends a clear message to governments that they cannot violate people's rights with impunity,” he said in a statement.
“It also demonstrates that with courage and commitment, communities - no matter how marginalised - can successfully stand up for their rights.”
Ten local residents from the waterfront community brought the case against the federal and Rivers state government, supported by the Socio-Economic Rights and Accountability Project group.
Those involved called for the terms of the ruling to be implemented in full.
Amnesty said it was concerned about the use of excessive force by the Nigerian military and police during forced evictions and called for an end to the practice.
More than two million have been affected by slum clearances across the country since 2000. - Sapa-AFP