WASHINGTON — The Department of Justice said Monday that a unit of CVS Caremark Corp. has agreed to pay $5.25 million to settle allegations that it reported false information on prescription drug prices to the government’s Medicare program.

Federal investigators said the company’s RxAmerica subsidiary reported false information about the prices of generic prescription drugs between 2007 and 2008. The Centers for Medicare and Medicaid Services used this information in a website called Plan Finder, which seniors could use to estimate their out-of-pocket drug expenses. But Department of Justice officials said the actual drug prices offered by the company were ‘‘in some cases significantly higher’’ than those submitted for use on the website.