Luxembourg prosecutors are seeking 18-month jail terms for two whistleblowers on trial over the “LuxLeaks” scandal.
The two former employees of auditing firm PricewaterhouseCoopers are accused of leaking documents to journalist Edouard Perrin, who faces a fine.
The papers revealed that Luxembourg offered huge tax breaks to international firms including Apple, Ikea and Pepsi.
The defence has called for a landmark judgement acquitting the men.
The trial began two weeks ago, and a verdict is not expected until mid-June.
As he summed up the prosecution’s case, deputy state prosecutor David Lentz argued that the actions of Mr Deltour and Mr Halet had amounted to theft, as they had violated a confidentiality agreement in their employment contract with PricewaterhouseCoopers (PwC).
Mr Lentz also told the court that Perrin’s actions went beyond the remit of a journalist, accusing him of manipulating Mr Halet into releasing the information.
“There are limits on freedom of expression,” he said. “It is not the press that’s on trial here, but this journalist who went further than his colleagues.”
He said that he had taken into consideration the revelations on “certain doubtful practices” exposed by the leaks, but that they had nonetheless broken Luxembourg’s laws.
But Mr Deltour’s lawyer urged the judges to make a landmark judgement by acquitting the men.
“The decision that you will take will write a new page in European law,” said William Bourdon. “It is a burden, but also an opportunity.”
Representing Perrin, defence lawyer Roland Michel said that the journalist had done nothing wrong
“My client has done only done one thing – reveal the truth”, he said. “To condemn him would be immoral and contrary to our rights.”
The files showed how Luxembourg granted lucrative tax breaks that saved firms including Apple, Ikea and Pepsi billions of dollars in taxes, at a time when Jean-Claude Juncker, now head of the European Commission, was prime minister.
In the past two years, the EU has pushed through tougher rules on taxation in the wake of the LuxLeaks release.
The documents were originally used for a 2012 report on French public television in collaboration with the BBC’s Panorama. They gained international interest in 2014 with the huge “LuxLeaks” dump of all 30,000 pages into the public domain.
LuxLeaks was the biggest expose of corporate tax deals until last month’s publication of the Panama Papers, which revealed links between a number of international leaders and offshore shell companies that can be used to hide or launder wealth.