PAINTER Fan Zeng, who fled China three years ago to seek artistic freedom in the West, has vowed to end all involvement in politics and concentrate on his art. In a telephone interview from Paris yesterday, Fan said politics was ''too complicated'' for him and he had decided to leave it to the politicians. Fan fled China in 1990 to seek ''freedom of expression and creativity'' in the West, but he returned to China in June after securing a promise from Beijing that he would not be punished. He spent more than two months in China settling his marital problems and divorcing his wife, Bian Baohua. They agreed to settle the matter out of court, having verified their separation with the Ministry of Civil Affairs. Fan plans to marry his longtime companion, Nan Li, in Paris next month before they both return to China. But he does not intend to settle in China permanently. He claims Beijing has granted him freedom to travel and issued him a passport to that effect. ''I am going to buy a villa somewhere in China, but will travel between Paris and China frequently,'' he said. According to the 55-year-old artist, he has been appointed professor of the Oriental Art Department at the Tianjin Nankai University, where he taught before his dash for freedom. He denied rumours that there was bad blood between him and the university as a result of his sudden departure in 1990. During his two-month sojourn in China, Fan said he met ''artists, intellectuals and academics'', but not Li Ruihuan, chairman of the Chinese People's Political Consultative Conference. ''Although we are friends, it doesn't mean we have to see each other all the time,'' he said. Fan plans to hold an exhibition in Hong Kong next year to show more than 100 paintings he completed during his three-year exile in Paris.