Andre Francois-Poncet, a French diplomat who specialized in German affairs and warned of Hitler's rise, died Sunday at his home in Paris. He was 90.

He served as French ambassador to Germany from 1931 to 1938, the years in which Hitler came to power.

Mr. Francois-Poncet warned repeatedly against the dictator's intentions, and about Germany's rearmament and war preparations. He characterized the ascendancy as the Nazis as "the victory of the Huns over the Germans."

He was imprisoned by the Gestapo for two years during World War II.

In the postwar years, he served as high commissioner for the French-occupied zone of Germany and later as France's first ambassador to the Federal Republic of Germany when it was established in 1955.

In addition to his assignments in Germany, Mr. Francois-Poncet was ambassador to Italy from 1938 until Italy entered the war against France in 1940. He then served Marschal Petain's Vichy government for Unoccupied France until his arrest by the Germans in 1943.

He retired from public service in 1955 to devote his time to writing for the conservative French daily, Le Figaro.

Mr. Francois-Poncet was known for his sardonic and witty observations. While serving as ambassador to Germany in the 1930s, he attended a dinner party given by Hitler for Anthony Eden.Eden and Hitler discovered that during the German offensive of 1918 they had fought opposite each other. After the dinner Mr. Francois-Poncet said to Eden: "And you missed him. You ought to be shot!"

Mr. Francois-Poncet was born at Provins, southeast of Paris, graduated from the Ecole Normale, and attended universities in Berlin, Munich and Heidelberg.He became a specialist in German language and culture.

He served in the French Army during World War I and was awarded the Croix de Guerre.

He began his public career with the foreign ministry during the war and was assigned to Bern, Switzerland. He entered politics as a member of the Chamber of Deputies in 1924.

Mr. Francois-Poncet was a president of the standing committee of the International Red Cross, a member of the French Academy, and the author of several autobiographical works and books on German literature and politics. He was a holder of the highest rank in the Legion of Honor, that of the Grand Cross.

He is survived by four sons and a daughter. His youngest son, Jean Francois-Poncet is head of the personal staff of French President Valery Giscard d'Estaing.