Two ex-PwC employees have been found guilty on charges relating to their involvement in a leak of their firm's data, and handed suspended sentences.
Antoine Deltour was given a suspended sentence of 12 months and a fine of €1,500 (£1,241), while Raphael Halet was handed a nine-month suspended sentence and a fine of €1,000 for their role in the so-called Luxleaks data leak.
Edouard Perrin, a journalist who used the leaked data for a broadcast made in 2012, was acquitted of charges against him.
The information obtained by Deltour and Halet revealed how over 300 companies had used Luxembourg as a tax haven to cut their tax bills.
The data was eventually used by the International Consortium of Investigative Journalists (ICIJ) to form their Luxembourg Leaks project.
Reuters reported that, outside the court, Deltour was greeted by supporters, while one of his lawyers, William Bourdon, called the decision "scandalous", saying that the country's justice system had sent a clear message to multinationals that they could "sleep tight".
A PwC Luxembourg statement read:
PwC Luxembourg stands by the advice it provided to its clients, all of which was given in accordance with applicable local and international tax laws and agreements and in accordance with the PwC Global Tax Code of Conduct, which has been in place since 2005.
According to a statement on website for a support group for Deltour, Deltour said:
Sentencing the citizens at the origin of LuxLeaks revelations is equivalent to sentencing the regulatory advancements which have been triggered by these revelations and which have been widely acclaimed across Europe. This is also a warning towards future whistleblowers, which is detrimental to citizen’s information and the good functioning of the democracy.
In the blog post, the ICIJ condemned the convictions of the two whistleblowers.
"This is a trial that should not have happened in the first place," said ICIJ director Gerard Ryle. "Antoine, Raphael and Edouard should all have been applauded and thanked for their roles in bringing the issue of corporate tax avoidance to the public's attention, not dragged through the courts and punished."