Here is a link to the court's judgement in that case which puts a different slant on the affair.

The court ruled that a public servant writing a book about the organisation they are employed by, in this case the European Commission, has to ask permission before doing so, and that the bloke in this case had not done so and was therefore at fault.

However it also said that if he had asked permission it would probably have been illegal for the Commission to have refused permission, even if it had wanted to.