A French court has ruled that Ryanair must pay €8.1m in damages for a breach of French labour law.
The violations are said to have taken place between 2007 and 2010.
An appeals court found the company guilty of paying workers under Irish contracts to save money on payroll and other taxes.
Ryanair has also been fined €200,000.
The carrier was originally ordered to pay the fine back in October of 2013, but it lodged an appeal.
The majority of the fine relates to alleged non-payment of social insurance and state pension contributions in France for Ryanair crews flying to/from Marseille.
The airline had said this was despite the fact that these people were employed on Irish contracts, operating on Irish registered aircraft.