In which language did Jean Paul Sartre write his books?

Jean Paul Sartre wrote his books in French language. Jean-Paul Sartre was a French existentialist philosopher, playwright, novelist, screenwriter, political activist, biographer, and literary critic. He was one of the leading figures in 20th century French philosophy, existentialism, and Marxism, and his work continues to influence fields such as Marxist philosophy, sociology, critical theory and literary studies. He was awarded the 1964 Nobel Prize in Literature but refused the honour.