UBS is enlisting a German former financial heavyweight as it prepares for an appeal in a high-stakes French criminal trial.

The Swiss wealth manager is looking to Theo Waigel, a German politician who was finance minister in Germany's government from 1989 to 1998, for help in its French tax evasion and money laundering case, according to German monthly «Manager Magazin» (in German). Neither Waigel, who is now 80, nor UBS commented on the report.

UBS is appealing a $5 billion fine imposed last February. Waigel possesses key institutional knowledge which is useful to the Swiss bank's defense plan, honed by chief lawyer Markus Diethelm. 

Decades-Old Directive

According to the German magazine, a European Union guideline from 2003 is poised to play a key role in the retrial, which begins in June. The directive safeguarded cross-border interest payments and required Swiss banks to notify EU member states if their citizens were earning interest in wealth held in Switzerland.

The directive was superseded three years ago, when the alpine nation began adopting automatic data-swapping agreements with the bloc. A key part of UBS' new defense plan is that a large portion of French wealth held at UBS wasn't undeclared – the bank had also been passing on withholding tax to France, though French officials wouldn't have known who the money stemmed from.

Waigel, an ally of former German chancellor Helmut Kohl, was instrumental in drafting the EU directive in the late 1990s. Together with his former negotiating partners, the ex-politico is reportedly being deployed to reconstruct the decades-old plan in order to support UBS' defense.