Cécile, a novel by Th. Fontane, published in instalments in 1886, and in book form in 1887. One of Fontane's social works, it is a triangular narrative with a Berlin setting. Its principal characters are von St Arnaud, a retired colonel, his wife Cécile, formerly the mistress of a minor prince, and Herr von Gordon, a civil engineer and reserve officer. St Arnaud neglects his wife, and Gordon associates with her. The affair culminates in Gordon's death in a duel at the hands of St Arnaud, the latter's flight, and Cécile's suicide.
The novel is remarkable for its picture of a fringe of Berlin high society, and for the account of spa life at Thale in the Harz, where the first part of the novel is set. It is also notable for the compassionate picture of the fallen Cécile, whose life has been blighted in childhood by a seduction connived at by her mother.