France and Kazakhstan have signed energy and business deals worth $6bn (£3.8bn) during a visit to Astana by French President Nicolas Sarkozy, BBC reported.
Kazakhstan also agreed to allow French military supplies to pass through on their way to Afghanistan.
Mr Sarkozy said he discussed concerns over Kazakhstan's rights record with President Nursultan Nazarbayev but had not come to "give lessons".
Kazakhstan has large oil and gas fields and is Central Asia's largest economy.
Mr Nazarbayev has ruled since the country gained its independence when the Soviet Union broke up in 1991.
Kazakhstan is being courted by a number of Western nations for its energy reserves and strategic position. It shares borders with China and Russia and is near Afghanistan.