Swiss billionaire and politician Christoph Blocher looks at paintings of Ferdinand Hodler during a guided visit for the media of his collection at the Fondation Gianadda in Martigny, Switzerland, December 6, 2019. REUTERS/Denis Balibouse REFILE - CORRECTING PAINTER'S NAME 

Swiss billionaire and politician Christoph Blocher poses with Leonard Gianadda in front of painting by Ferdinand Hodler "Vue du Leman depuis Chexbres" after a guided visit for the media of his collection at the Fondation Gianadda in Martigny, Switzerland, December 6, 2019. REUTERS/Denis Balibouse 

A visitor looks at paintings by Ferdinand Hodler that belongs to Swiss billionaire and politician Christoph Blocher and that are exposed at the Fondation Gianadda in Martigny, Switzerland, December 6, 2019. REUTERS/Denis Balibouse. REFILE - CORRECTING PAINTER'S NAME 

Swiss billionaire and politician Christoph Blocher poses in front of a painting by Ferdinand Hodler "Vue du Leman depuis Chexbres" after a guided visit for the media of his collection at the Fondation Gianadda in Martigny, Switzerland, December 6, 2019. REUTERS/Denis Balibouse 

Swiss billionaire and politician Christoph Blocher poses with Leonard Gianadda in front of painting by Ferdinand Hodler "Vue du Leman depuis Chexbres" after a guided visit for the media of his collection at the Fondation Gianadda in Martigny, Switzerland, December 6, 2019. REUTERS/Denis Balibouse 

Visitors look at paintings by Ferdinand Hodler that belongs to Swiss billionaire and politician Christoph Blocher and that are exposed at the Fondation Gianadda in Martigny, Switzerland, December 6, 2019. REUTERS/Denis Balibouse. REFILE - CORRECTING PAINTER'S NAME 

Light projections show the painting "Maibild" (May picture) from 1925 of late German-born artist Paul Klee during a media preview of the Illuminated Art Zuerich Ferdinand Hodler & Paul Klee lightshow at the Maaghalle event hall in Zurich, Switzerland August 7, 2019. Picture taken August 7, 2019. REUTERS/Arnd Wiegmann 

A light projection shows the painting "Stilleben mit Distelblume" (Still life with thistle bloom) from 1919 of late German-born artist Paul Klee during a media preview of the Illuminated Art Zuerich Ferdinand Hodler & Paul Klee lightshow at the Maaghalle event hall in Zurich, Switzerland August 7, 2019. Picture taken August 7, 2019. REUTERS/Arnd Wiegmann 

Light projections show the painting "Eiger, Moench, Jungfrau in der Morgensonne " (Eiger, Moench, Jungfrau in the morning sun) from 1908 of late Swiss artist Ferdinand Hodler during a media preview of the Illuminated Art Zuerich Ferdinand Hodler & Paul Klee lightshow at the Maaghalle event hall in Zurich, Switzerland August 7, 2019. Picture taken August 7, 2019. REUTERS/Arnd Wiegmann 

Light projections show the painting "Blaue Felsen in der Nacht" (Blue rocks at night) from 1939 of late German-born artist Paul Klee during a media preview of the Illuminated Art Zuerich Ferdinand Hodler & Paul Klee lightshow at the Maaghalle event hall in Zurich, Switzerland August 7, 2019. Picture taken August 7, 2019. REUTERS/Arnd Wiegmann 

Light projections show the painting "Der Auserwaehlte, zweite Fassung " (The chosen one, second version) from 1903 of late Swiss artist Ferdinand Hodler during a media preview of the Illuminated Art Zuerich Ferdinand Hodler & Paul Klee lightshow at the Maaghalle event hall in Zurich, Switzerland August 7, 2019. Picture taken August 7, 2019. REUTERS/Arnd Wiegmann 

People stand in front of the painting "Withdrawal from Marignano" from 1897/98 by late Swiss artist Ferdinand Hodler during a media preview of the exhibition "1515 Marignano" at the Landesmuseum (national museum) in Zurich March 25, 2015. The exhibition "1515 Marignano" commemorates the 500th anniversary of the battle of Marignano in Italy which Switzerland lost against France. The exhibition is opened to the public from March 27 to June 28. REUTERS/Arnd Wiegmann

Employees display the painting "Summer Landscape Near Interlaken" by late Swiss artist Ferdinand Hodler (1853-1918), as auctioneer Claudia Steinfels (L) awaits bids during Sotheby's auction of 114 pieces of Swiss art in Zurich June 14, 2010. REUTERS/Arnd Wiegmann (SWITZERLAND - Tags: SOCIETY BUSINESS) 

Auctioneer Claudia Steinfels (L) brings the gavel down as the painting 'The Mower' from 1910 by the late Swiss artist Ferdinand Hodler (1853-1918) is sold during a Sotheby's auction of 135 pieces of Swiss art, in Zurich November 26, 2008. The painting was sold for 1,426,500 Swiss Francs ($ 1,186,286). REUTERS/Arnd Wiegmann (SWITZERLAND) 

Employees display the painting 'The Mower' from 1910 by late Swiss artist Ferdinand Hodler (1853-1918) during a Sotheby's auction of 135 pieces of Swiss art, in Zurich November 26, 2008. The painting was sold for 1,426,500 Swiss Francs ($ 1,186,286). REUTERS/Arnd Wiegmann (SWITZERLAND) 

Employees display the painting 'Lake Geneva with Jura (Landscape Rhythm of Forms)' from 1909 by late Swiss artist Ferdinand Hodler (1853-1918) during Sotheby's auction of 154 pieces of Swiss art in Zurich May 27, 2008. REUTERS/Arnd Wiegmann (SWITZERLAND) 

Auctioneer Claudia Steinfels calls for bids for the painting "Lake Geneva with Jura (Landscape Rhythm of Forms)" by late Swiss artist Ferdinand Hodler during Sotheby's auction of 154 pieces of Swiss art in Zurich May 27, 2008. REUTERS/Arnd Wiegmann (SWITZERLAND) 

An employee of Sotheby's auctioneers adjusts the painting 'Lake Geneva with Jura (Landscape Rhythm of Forms)' from 1909 by late Swiss artist Ferdinand Hodler (1853-1918) before an auction preview in Zurich May 22, 2008. The painting will be part of 154 pieces of Swiss art, offered in an auction on May 27. REUTERS/Arnd Wiegmann (SWITZERLAND) 

A worker adjusts the missed picture "Landscape in Ticino" of Swiss artist Ferdinand Hodler after arriving in the Kunstmuseum Bern for the Hodler exhibiton 'A Symbolist Vision' in Bern April 28, 2008. REUTERS/Ruben Sprich (SWITZERLAND) 

A worker adjusts the missed picture "Landscape in Ticino" of Swiss artist Ferdinand Hodler after arriving in the Kunstmuseum Bern for the Hodler exhibiton 'A Symbolist Vision' in Bern April 28, 2008. REUTERS/Ruben Sprich (SWITZERLAND) 

A worker drills a hole for the missed picture "Landscape in Ticino" of Swiss artist Ferdinand Hodler after arriving in the Kunstmuseum Bern for the Hodler exhibiton 'A Symbolist Vision' in Bern April 28, 2008. REUTERS/Ruben Sprich (SWITZERLAND) 

The missed picture "Landscape in Ticino" of Swiss artist Ferdinand Hodler is seen after arriving in the Kunstmuseum Bern for the Hodler exhibiton 'A Symbolist Vision' in Bern April 28, 2008. REUTERS/Ruben Sprich (SWITZERLAND) 

Sotheby's employee Sebastien Maret adjust Ferdinand Hodler's "Les Dents du Midi" after a news conference in Champery, October 11, 2007. The presale estimate of $4 to 6 million is the highest for a painting by the Swiss artist. The version, which has not been viewed in public for 57 years, will be auctioned by Sotheby's in Zurich on November 27, 2007. REUTERS/Stefan Wermuth (SWITZERLAND) 

Staff members hold up a painting titled "Eiger, Monk And Virgin Above A Sea Of Fog" (1908), one of three different versions of the snowed in mountain summits by Swiss artist Ferdinand Hodler, during an auction preview at Sotheby's in Geneva, Switzerland, November 11, 2005. The painting, considered to be one of Hodler's most sophisticated ones, will be on sale at an auction of Swiss Art in Zurich on November 29. REUTERS/Denis Balibouse 

Staff members hold up a painting titled "Eiger, Monk And Virgin Above A Sea Of Fog" (1908), one of three different versions of the snowed in mountain summits by Swiss artist Ferdinand Hodler, during an auction preview at Sotheby's in Geneva, Switzerland, November 11, 2005. The painting, considered to be one of Hodler's most sophisticated ones, will be on sale at an auction of Swiss Art in Zurich on November 29. REUTERS/Denis Balibouse