The Interior Minister, Ruth Dreifuss, and two of her senior officials have been accused of abusing their authority by allowing paintings in the famous Gustav Rau art collection to go abroad.
The legal challenge against the interior ministry is the latest twist in a complex saga surrounding the priceless collection, which contains masterpieces by Renoir, Monet, Degas, Fra Angelico, Watteau, Canaletto and El Greco.
At the heart of the dispute is a battle for control of the collections between the four foundations created by Dr Rau, and the German billionaire philanthropist's entourage. Analysts say the outcome of the proceedings could have important financial and cultural implications.
Dreifuss, the Interior Ministry secretary general, Claudia Kaufmann, and her deputy, Bruno Ferrari-Visca, are accused of failing in their duties by allowing paintings in the collection to go abroad.
Lawyers are also questioning the ministry's decision to go back on a decision not to allow members of Gustav Rau's entourage access to the paintings.
The lawyers, acting for two of the four foundations created by the billionaire German doctor, say the foundations, in Zurich and Geneva, did not give their permission for the paintings to be sent abroad.
They accuse Dreifuss and her colleagues of "diminishing a precious heritage which is in danger of never being seen in Switzerland again".
Ninety-five paintings were allowed to go to Japan for an exhibition. They have since travelled to Paris and Rotterdam, and have yet to return to Switzerland.
Close associates of Rau are suspected of being responsible for the disappearance of 60 paintings from the collection, as they attempted to dismantle the foundations shortly after Rau was diagnosed with a degenerative brain illness.
To save the foundations, the Interior Ministry, which oversees their management, placed three of them under trusteeship in 1998. Yet two years later, it performed a U-turn, ending the trusteeship and naming Dr Rau and a lawyer acting for his entourage members of the council of the three foundations.
The ministry says the paintings are the personal property of Dr Rau and not of the foundations. What is at question is Rau's mental state and his ability to manage his affairs.
The Swiss Federal Court backed the findings of the justice authorities in Monaco, which considered him incapable of sound judgement due to his degenerative condition.
Yet the Interior Ministry and the Zurich judiciary support a ruling by a court in the German city of Baden-Baden that Rau was indeed capable of managing his own affairs and could decide for himself the members of the foundations' governing bodies.
Gustav Rau was born in Stuttgart in 1922, the son of a wealthy German industrialist. Having sold off his father's business he became a doctor specialising in tropical medicine and paediatrics. He worked in Africa and in 1983 built a hospital in the then Zaire.
At the end of the 1960s, he began compiling his unique collection, which spans some 500 years of European art. He set up the four foundations, the aim of which was to fund aid and development projects in the developing world.
by Roy Probert