PARIS, June 16 (AP)—Mr. Georges Pompidou, who was fired as Gen. Charles de Gaulle’s Prime Minister a year ago, was elected President of France last night with a margin of victory greater than that won by Gen. De Gaulle in the last Presidential election in 1965. The French Interior Minister, Mr. Raymond Marcelin, said Mr. Pompidou would assume his functions as head of State on Friday. Mr. Pompidou is expected to name Mr. Jacques Chaban-Delmas, the handsome tennis-playing President of the National Assembly, as his PM later this week. The new PM, who will take over from Mr. Maurice Couve de Murville, will not be named until after Mr. Pompidou has been installed as President.