Belgian authorities are to sue Ryanair in the Irish courts for the return of €2.5 million in state aid that the European Commission has declared illegal.
The regional government of Wallonia, the French-speaking part of the country, has engaged an Irish firm of solicitors to pursue the action.
The European Commission ruled last year that part of the Walloon government's subsidy to Ryanair for using Charleroi airport, near Brussels, contravened EU rules on state aid.
The EU ordered the Belgian government to recover some of the subsidies already paid to the airline.
Ryanair has appealed the commission's decision to the European Court of Justice in Luxembourg but has agreed to lodge €4.5 million into a frozen account, pending the judgement.
Besides ordering the recovery of some subsidies, the commission demanded that "one-shot contributions" for the training and accommodation of pilots and the opening of new lines should be justified by the airline.
The Walloon authorities say that Ryanair has failed to provide a satisfactory justification for these payments and has engaged McCann Fitzgerald Solicitors, who have an office in Brussels, to recover €2.5 million from the airline.
The Belgian authorities, who are negotiating new terms with Ryanair for the use of Charleroi, are under pressure from the European Commission to recover the unauthorised state aid without delay.
