Even if you defraud a billionaire, be prepared to pay restitution.

The district court of Düsseldorf has ordered one of Germany’s most prominent art advisers to pay €18.7 million ($20.8 million) to the heirs of a former client, billionaire Berthold Albrecht, the co-owner of the Aldi supermarket chain who died in 2012. The decision, made on Wednesday, largely upholds an earlier ruling made by the court in January 2015.

Before his downfall, the adviser, Helge Achenbach, was one of Germany’s top art-world figures. He had a reputation for identifying works that would go on to appreciate substantially in value and helped top-tier collectors, including Albrecht and pharmaceutical executive Christian Boehringer, build up their blue-chip holdings.

Three years ago, however, things began to unravel for Achenbach. In a dramatic trial that was followed closely by Germany’s tabloid press, the adviser confessed to secretly increasing his commission by tampering with receipts to add markups to his agreed rate. In March 2015, Achenbach was sentenced to a six-year prison term and ordered to pay damages that have now been confirmed at €18.7 million ($20.8 million).

In the first ruling dated January 2015, the court ordered the adviser to pay €19.4 million ($21.6 million) in damages. After a subsequent appeal to Düsseldorf’s higher district court, the case was sent back to the regional court on procedural grounds. On Wednesday, presiding judge Joachim Matz largely upheld the previous 2015 ruling, though he slightly reduced amount of damages, according to the German daily Rheinische Post.

Achenbach’s troubles date back to June 2014, when Berthold Albrecht’s widow accused the adviser of defrauding the family out of at least €18 million ($20 million) after an audit revealed inconsistencies in his invoices. The family then filed a complaint with the state prosecutor in Essen.

In his decision, the judge stated that Achenbach enjoyed the “personal trust” of his client and characterized their relationship as a “close friendship” that extended beyond professional art advising.

The bulk of the sum will be paid to the family from the €8.5 million ($9.4 million) generated by the forced sale of Achenbach’s 1,600-piece collection. His holdings were sold in 2015 at an auction orchestrated by the court-appointed bankruptcy administrator.

Achenbach was released on parole last year—but his legal woes are far from over. He is still facing a separate €5 million ($5.6 million) lawsuit over the matter brought by Albrecht’s heirs.

Achenbach’s lawyers could not immediately be reached for comment.