The Belgian Walloon region has been given an extra 15 days to say how much illegal state aid it will take back from Ryanair.
The European Commission said they expect a response from the Belgian regional authorities, owners of Charleroi airport, by the start of July.
In February the Commission ordered Ryanair to repay several million euros in subsidies after calling some of the handouts granted for using the airport illegal under EU law.
"We received some information at the end of May, but that information does not tell us exactly how they're going to do the calculations and how they're going to recover the amounts involved," Commission spokesman Mr Gilles Gantelet said.
Mr Gantelet said the Commission had told the Belgian authorities what was legal and what was illegal. He also said the Commission had not yet been officially told what arrangements the region, the airport and Ryanair would make to stop the illegal state aid.