Activists are calling on French conglomerate Bollore to return land, or compensate farmers, over disputed concessions for plantations in Cambodia and three African countries.

The Peasants' Confederation and other farmers' rights groups sent a letter to Bollore Thursday ahead of a shareholders' meeting. Bollore is the largest shareholder of Socfin, which has been accused by activists of land grabs in Cambodia, Liberia, Cameroon and Ivory Coast.

Talks began last year over farmers' claims that they weren't adequately compensated for losing their land.

Bollore had no immediate comment Thursday. Socfin has said it is committed to "responsible consideration of ... communities affected by growers and mills."

Cambodia's government granted three concessions to Socfin and a Cambodian partner to grow rubber on land where the ethnic minority Bunong people resided, prompting conflict.