Poet and writer Louis Aragon, 85, a leading French communist intellectual for a half-century and a founder and former leader of the Surrealist movement, died at his home here Friday. The cause of death was not reported.

"France is grief-stricken by the death of one of its greatest writers," President Francois Mitterand, a socialist, said on hearing of Mr. Aragon's death. "The magic of his poetry and the force of his work put him in the first rank of our national literature. I bow before his memory."

Mr. Aragon, a communist since 1927, became one of the voices of the French anti-Nazi resistance during World War II, after being captured while serving in a tank division, escaping and reaching then-unoccupied France.

For much of his life his name was closely associated with that of his wife, the Russian-born novelist Elsa Triolet, a sister-in-law of the Soviet poet Vladimir Mayakovsky. She defended the same political and literary causes as her husband to the extent that friends dubbed them "Elsaragon."

The couple met at a celebrated cafe-restaurant in the Paris district of Montparnasse, The Coupole. Mr. Aragon called his wife "his love, his youth." She died in 1970.

Elsa Triolet was a prominent member with him of the Surrealist movement, an artistic revolt in the fertile postwar 1920s against all forms of order and convention.

Mr. Aragon, with his friend Andre Breton, founded the magazine "Litterature" after World War I, sharing a widespread reaction to the horrors of the war in which France suffered heavy losses. In the 1930s, he abandoned Surrealism in favor of communist-inspired "socialist realism."

Mr. Aragon joined the Communist Party after flirting with outright anarchy and used his talents as novelist, essayist and journalist to further its cause. But he also often disagreed with it, and remained a political nonconformist.

During the cold war after World War II, he vigorously defended Stalinism, but then declared himself "overwhelmed" by the 1956 revelations of the Soviet 20th party congress on Stalin's crimes, while his own party questioned them.

In 1966, Mr. Aragon denounced the Soviet persecution of writers Andrei Sinyavski and Yuli Daniel, found "guilty" of passing books clandestinely to the West, where they were then published.

Two years later he waged a vigorous campaign against the Soviet invasion of Czechoslovakia, so that his communist weekly "Les Lettres Francaises" was banned in Eastern Europe. The weekly ceased publication in 1972.

But in 1980 Mr. Aragon publicly defended the French Communist Party's support for the Soviet intervention in Afghanistan.

As a novelist, Mr. Aragon began a cycle of "real world" novels with "Les Cloches de Bale" in 1935, continued in "Les Beaux Quartiers" (1936) and "Aurelien" (1945).

He produced a series on the communists between 1949 and 1951, dealing with France at the start of World War II, while his later novels, "La Mise a Mort" (1956) and "Henri Matisse" (1971) were strongly autobiographical.

But it was his poems, particularly the militant poems like "Le Creve-Coeur" (Heartbreak) and "Les Yeux d'Elsa" (Elsa's Eyes), written during the World War II resistance in 1941 and 1942 and distributed clandestinely, which perhaps touched the widest public.