Geert Jan Jansen (born 1943) is a Dutch painter and art forger, who was arrested in 1994. Geert Jan Jansen was born in Waalre in the Netherlands. His engineer father was fond of art and Jansen became an art student. He befriended a US art dealer, , who ran a gallery called Mokum in Amsterdam. Later, Jansen opened his own galleries, Jacob and Raam, but was not particularly successful. When his business went badly, he decided to sign posters of Karel Appel's lithographs and sell them as originals. Later, he made his first Karel Appel forgery and sold it for 2,600 guilders. Thus encouraged, he sent another forgery to London; auction house sent a photograph to Appel, who stated that it was genuine. The gouache was sold at a record price. In 1981, Dutch police were informed about a forged Bart van der Leck painting. They searched Jansen's house in Edam but found nothing. They did find 76 forged Appel lithographs in the ceiling of a local warehouse, but charges were not pressed. Short of evidence, the attorney general cut a deal with Jansen: He would not be charged if he would not make forgeries for three years. In 1988, Jansen released another batch of Appel paintings. When they were found to be forgeries, gallery owners blamed each other. In June 1988, police confiscated hundreds of Appel forgeries from the MAT gallery in Amsterdam. The owner of the gallery said that he had bought 100 Appel forgeries from the Tripple Tree Gallery, who had bought them from a dealer Henk Ernste in Paris. Ernste was later arrested but the case was settled with a 5.5 million guilder fine. During the furor, Jansen moved from the Netherlands to France with his mistress. In March 1994, "Jan van den Bergen" came to the auction house Karl & Faber in Munich. He claimed to be an art dealer from Orléans and presented his business card. With him he had a Chagall drawing, an Asger Jorn gouache and a Karel Appel painting. The first two had written certificates of authenticity. He wanted them to be auctioned quickly and left in a hurry. Expert Sue Cubitt of the auction house had the works examined. The Chagall certificate had a misprint and she became suspicious. Jan Nieuwenhuizen Segaar, a representative of Karel Appel, contacted the artist who said that work was his but Cubitt was still