Although Sotheby's are selling works by the likes of Monet, El Greco and Tiepolo from the collection of the late German collector this summer, Bonhams will offer Jean-Honoré Fragonard's (1732-1806) portrait of François-Henri d'Harcourt at a special 94-lot sale in London's New Bond Street on December 5.
The estimate has been set 'in excess of £10m'.
Dr Rau died in 2002 and bequeathed his extraordinary collection to UNICEF Germany who are selling the works. Three auctioneers are sharing the 533 works with approximately £16m worth of paintings, sculpture and decorative arts to be offered at different Sotheby's sales over the next few months, while Lempertz of Cologne sold their first tranche of the collection for €1.8m (£1.59m) in May.
Lempertz will also be offering a second part of the Dr Gustav Rau collection on November 15-16 which includes 250 Old Master paintings, sculpture and decorative art, meaning the total estimate of the items consigned to Lempertz is approximately €8m.
A statement from UNICEF said that the lots were divided up between the three separate salerooms after putting out a call for tenders and selecting the companies on the basis of their "convincing and favourable terms". The proceeds will be used to benefit UNICEF.
As specified in Dr Rau's bequest, the core of the collection consisting of 152 paintings and sculptures is to be on public exhibit at the Arp Museum in Remagen near Bonn until 2026.
'Fantasy Portrait'
The Fragonard itself is one of 14 so-called 'Fantasy Portraits' painted by the French artist in 1769, eight of which are now in the Louvre and only two remain in private hands. These works, whether painted from life or invented, were attempts to represent the vision of an inspired poet and are typified by highly coloured and broad brush strokes. The style was referred to by some contemporaries as the 'swordplay of the brush'.
Bonhams' director of Old Master paintings Andrew McKenzie said that this was a work of "dazzling accomplishment" and was one of the works for which the artist acquired his reputation.
The subject, François-Henri d'Harcourt, was a high-ranking nobleman who served as a general in the French army, as well as governor of Normandy and guardian to the young Louis XVI. He was elected a member of the Académie Française in 1788 but left France the following year following the 1789 Revolution.
Serving as ambassador to the British Court for the exiled Louis XVIII from 1792, he died in Staines in Middlesex in 1802.
This picture has only changed hands once in its 250 year history when Dr Rau acquired the picture from the Harcourt family in 1971.
More recently it has been on temporary loan to the Getty in Los Angeles.
The picture will be one of the most important sales in the inaugural season of auctions to be held in Bonhams new saleroom in New Bond Street which is due to open in October.
Among the other works in the December 5 sale are a 15th century depiction of the Crucifixion by an unknown German artist (est: £1m-1.5m); a portrait of the Duchess of Montebello by Pierre-Paul Prud'hon (est: £700,000-1,000,000); Le grand noyer à l'Hermitage by Camille Pissarro (£200,000-3000,000); and Courtyard with flowers by Joaquín Sorolla y Bastida (£150,000-200,000).
