In a video posted last month on social networks after Manchester United eliminated PSG from the Champions League, Evra allegedly made two explicitly anti-gay insults about PSG as he responded to comments made online about the French club.
The investigation, led by a Paris police unit, was opened after gay rights groups lodged a complaint.
PSG has condemned Evra’s derogatory remarks, but United declined to comment on the posts because Evra no longer plays for the club.
The 37-year-old Frenchman played for three-time European champion United nearly 400 times from 2006-14. He captained the club on several occasions. He was also named France captain at the 2010 World Cup but was stripped of the captaincy during the tournament after the team went on strike at training.