Two-time Champions League winner Gunnarsdottir has won a landmark ruling against former club Lyon, following their failure to pay her a full salary after she was signed off on maternity leave in April 2021.
A statement from FIFPRO read: "FIFPRO congratulates Sara Bjork Gunnarsdottir on her successful claim against Olympique Lyonnais over the club's failure to pay her full salary during pregnancy.
"We are pleased to have assisted her in achieving the first ruling of its kind since FIFA's maternity regulations came into force in January 2021.
"It is extremely important for women footballers and the women's game that these mandatory maternity regulations are both implemented and enforced at national level."
Previously, Gunnarsdottir told all to The Players' Tribune: "I didn’t have any reason to think anything would go wrong. Until I didn’t get my first paycheck. All that was deposited was just a small percentage from social security.
"To be fair, there was a lot of logistical stuff to deal with, so I didn’t think too much of it. Probably a clerical error. But, I checked with the other players just to be sure. They were paid, right on time."
The 32-year-old later revealed in the interview that then club director Vincent Ponsot initially ignored questions about two months of missing pay, before responding by stating that Gunnarsdottir would not be paid beyond month three, ignoring FIFA regulations.
"Lyon refused to give a clear answer on what the criterion was that was being applied," She explained: "Finally, Dietmar told Vincent that FIFPRO was going to fight this at the FIFA level.
"Vincent said: 'If Sara goes to FIFA with this, she has no future in Lyon at all.'"
Prior to the incident, the midfielder - who is Iceland's leading appearance maker at international level - helped Lyon win Champions League titles in 2020 and 2022. The 32-year-old insisted she is now 'very happy' at Juventus - whom she departed for in July 2022 - where she has a contract through to 2024.