France's health products safety agency is advising users of the drug - the brand name for benflourex in France - from 2006 to 2009 to see their doctor to check for possible heart valve problems.
The agency said Tuesday that about 5 million people used Mediator starting in 1976.
The European Medicines Agency pulled benflourex from the market last year, saying it had little effect on diabetes and might lead to a dangerous thickening of heart valves.
In September, European regulators pulled blockbuster diabetes drug Avandia off the market because of alleged links to heart attacks.
