It wasn't a lie, as such. It involved the presentation of incomplete information with respect to which more than one interpretation was possible, and an insinuation that the most damaging interpretation was the correct one, when the additional information needed to aid in reaching a proper interpretation appears either to be absent or not conclusively to support the more damaging interpretation. In other words, it was misleading rather than a lie. Yes, I'm a pedant. ;)
This may well also an example of the above. The players from that academy are sent to a Danish club under a contract quoted in a Danish newspaper that's a part of that association of press outlets sharing the Football Leaks information. And the quoted clause 3.1 of the contract in question imposed a prohibition on the Danish club selling a player from the academy without MCFC's express consent, which on the face of it is a clear breach of the rules governing third-party ownership (TPO). EXCEPT for one thing.
The opening words of clause 3.1 were: "Subject to clause 3.5". In other words, clause 3.1 can't be read on its own but needs to be taken in conjunction with clause 3.5. So, one would presume, if the paper had access to clause 3.5 and that clause substantiated guilt on City's part, it would print details of that contractual provision. It didn't. Which suggests that either the relevant part of the contract wasn't available or it was available but didn't support the desired thrust of the story.
This episode pretty neatly encapsulates the way the press as a whole have dealt with the entirety of the Football Leaks material with regard to City. I fully acknowledge that City might be guilty of rule breaches in a number of areas and if we are, we have to take the punishments on the chin. But the way the allegations have been reported in the media shows that many outlets demonstrably prize sensationalism above good faith in their coverage of MCFC.
EDIT - Just to add, to be fair, that even the British press didn't, as far as I recall, run with the Right to Dream story given the flimsy basis of the original article. But I do remember a number of individual journalists retweeting the Danish piece with suitably prejudiced comments, proving themselves to be either intellectually dishonest or morons (I suppose with some of them we should allow for both possibilities).