New Delhi, Dec. 16 -- Ex-Congolese rebel leader Roger Lumbala was sentenced Monday in France to 30 years in prison over atrocities committed two decades ago during the Second Congo War, in a verdict that rights groups hailed as overcoming long-standing impunity in the Congo.

Lumbala was found guilty in a Paris criminal court on charges of "complicity of crimes against humanity." A lawyer for Lumbala, who has ten days to file an appeal, called the sentence excessive.

The 67-year-old led the Congolese Rally for National Democracy, a rebel group backed by neighboring Uganda and accused of atrocities against civilians, particularly targeting the Nande and Bambuti ethnic minorities in eastern Congo in 2002 and 2003.

The group committed wide...