France has announced a substantial aid package worth some 500m euros ($627m; £344m) over five years for Cameroon.
French Minister for International Development Brigitte Girardin said it was the largest aid sum France had ever promised to a sub-Saharan country.
She said she hoped the money would be used to reduce poverty. Cameroon Prime Minister Ephraim Inoni said it would be used "judiciously and transparently".
More than a quarter of Cameroon's national debt has been written off.
Last month, creditors including the World Bank and the International Monetary Fund agreed to reduce 27% of Cameroon's total debt.
A special committee, involving French and Cameroon officials and aid workers, has been set up to ensure that the French aid is used properly.
Some of the money is being earmarked to upgrade the roads in the economic capital, Douala.
The BBC's Jean David Mihamle in Cameroon says that local businessmen fear that most of the contracts will end up going to French companies, which can more easily meet the "international standards" required to submit bids.