WASHINGTON, Dec 7 (Reuters) - The U.S. Justice Department said on Tuesday it reached a settlement with Microsoft Corp (MSFT.O) resolving allegations that the company discriminated against non-U.S. citizens in its hiring process. Microsoft asked job applicants for unnecessary immigration documents to prove they could work for the company without needing its sponsorship for work visas, the department said.It said an investigation found that Microsoft discriminated against at least six lawful permanent residents based on their immigration status by asking them to show a Permanent Resident Card to prove they had permission to work without employer sponsorship. Under the settlement, Microsoft will overhaul parts of its hiring process to ensure the company is following U.S. law, which prohibits employers from asking for documents when they are not required, the Justice Department said. We hire and confirm employment eligibility for tens of thousands of people, and a handful were mistakenly asked for extra information or documentation," a Microsoft spokesperson said in a statement. "We appreciate we need to prevent these mistakes and have worked to address these issues and improve our internal processes as part of our commitment to compliance," the spokesperson said.