The National Directorate of Management Control (DNCG) confirmed the French club's relegation to Ligue 2 on Tuesday.
The club president, John Textor, and director of football Mickael Gerlinger were interviewed this Tuesday by the body to rule out this scenario, following the initial decision dated November 15th.
At that time, in the winter, the organisation had already warned that the club would be relegated at the end of the season if it didn't provide the guarantees required due to a debt of €175 million (£149 million).
Textor showed confidence "in the figures" and guaranteed that the club would "make several hundred million euros in the coming months".
American Textor sold his 43% stake in Premier League outfit Crystal Palace earlier in the week. Lyon have reduced their salary bill and sold Rayan Cherki to Manchester City and Maxence Caqueret to Como.
According to the BBC, they were sold for £190 million to Woody Johnson, the owner of the NFL's New York Jets.
Lyon have reduced their salary bill with attacker Alexandre Lacazette and goalkeeper Anthony Lopes released.
Textor said his Eagle group has also put £70 million into the club.
"Thanks to the equity contributions from our shareholders and the sale of Crystal Palace, our cash position has improved considerably, and we have more than sufficient resources for the 2025-2026 season," said the club statement.
'Sadness'
Lyon qualified for next season's Europa League after finishing sixth in the French top-flight.
If their relegation is confirmed, they would be replaced in Ligue 1 by Reims.
Lyon won seven consecutive French titles between 2002 and 2008, under Aulas.
"It's a terrible blow to all those who love Lyon", Aulas said on X on Tuesday.
"For 36 years I made sure that such a situation could not happen.
"I gave everything to build a solid, respected, ambitious club that was financially healthy.
"Today, it's sadness that dominates. And an immense failure to understand," the 76-year-old added.
Only five clubs have won Ligue 1 more often. Paris Saint-Germain hold the record with 13 titles.
Lyon are set to begin their pre-season on July 7th.
Lyon qualified for next season's Europa League after finishing sixth in the French top-flight.
If their relegation is confirmed, they would be replaced in Ligue 1 by Reims.
However, the punishment remains in place and Paulo Fonseca's side are now in dire straits.