Lawyers for Guy and Alec argued that carrying out the tax adjustment along with a criminal trial was unconstitutional and amounted to being tried for the same case twice. (Representational Image)
Several members of the Wildenstein art-dealing dynasty went on trial in Paris on Monday charged with stashing hundreds of millions of euros in inheritance money out of the reach of the French taxman.
Family patriarch Guy Wildenstein, 70, faces up to 10 years in prison for tax fraud and money laundering in a multi-generational inheritance squabble worthy of a soap opera.
However, court proceedings got off to a dry start as lawyers argued over whether the trial contravened constitutional safeguards against being judged twice for the same crime.
The Franco-American Guy Wildenstein is the heir of three generations of wealthy art dealers and thoroughbred racehorse breeders.
French tax authorities say he owes them more than 550 million euros ($600 million) in family money that was hidden after the death of his father Daniel in 2001 and brother Alec in 2008.
Alec became famous during his messy divorce from Swiss socialite Jocelyne Perisse, nicknamed "Bride of Wildenstein" for her extreme facial cosmetic surgeries, reportedly to make her look more catlike.
The divorce was the first action by a series of women who felt hard done by the Wildenstein men that forced the family to lift the veil of secrecy over its fortune.
The second wives and widows of Daniel and Alec rose up against the family over their slice of the inheritance, accusing Guy of hiding much of his inherited fortune via a web of opaque trusts in tax havens.
This piqued the interest of French investigators who began probing the case in 2010 and in 2014 demanded the tax adjustment of 550 million euros.
The dynasty had valued Daniel's estate in 2008 at just $61 million after Guy took over as president of the family's art gallery empire, which is based in New York.
That figure was despite assets including a host of works by Rococo painter Fragonard and post-Impressionist Bonnard and a stable of thoroughbred horses including Ascot Gold Cup winner Westerner.
Other assets included a vast real estate portfolio, with the jewel in the crown a luxurious Kenyan ranch which provided the backdrop for the film "Out of Africa".
Most of these assets were registered in tax havens.
In 2002 Guy and Alec Wildenstein handed over bas-reliefs sculpted for Marie-Antoinette, the wife of Louis XVI, to pay a 17.7 million euro tax bill.'Dallas-upon-Seine'
Guy Wildenstein is appearing alongside his nephew Alec Jr and Alec's widow Liouba Stoupakova for a month-long trial in a saga which has been dubbed "Dallas-upon-Seine".
Lawyers for Guy and Alec argued that carrying out the tax adjustment along with a criminal trial was unconstitutional and amounted to being tried for the same case twice.
A notary, two lawyers and two managers of the secret trusts held in Guernsey and the Bahamas are also in the dock.
In a rare interview three months ago, Guy Wildenstein said he knew little about tax, declaring: "My father never used to talk to me about his business affairs."
He says there was no legal obligation to report trust-held assets on his father's death.
According to the French investigation, the US tax authorities will also pursue unpaid taxes for artworks.