Francillon, James (1802–1866), judge and legal writer, was born on 21 November 1802, the sixth son of Francis Francillon and Frances Brook, daughter of Thomas Fennings, both of Harwich, Essex. He was descended on his father's side from a Huguenot family settled in England since 1685. Educated at the King's School, Rochester, he became an articled clerk in East Stonehouse, Devon, and in 1824 joined the firm of Wiltons in Bristol as conveyancing clerk, later being admitted an attorney. In November 1828 he entered Gray's Inn, and was called to the bar in 1833.

Francillon went on the Oxford circuit, enjoying a fair practice, but as an able conveyancer was chiefly employed in chamber work. In 1838 he married Lucy, daughter of Thomas Augustus Gale. In 1847, when the modern county courts were constituted, he was appointed judge for the Gloucestershire district, later becoming also a magistrate for Gloucestershire and Wiltshire, and deputy chairman of the Gloucestershire quarter sessions. While living in Cheltenham he attended the Unitarian chapel and was a friend of the Unitarian social reformer Henry Solly.

Francillon was regarded as one of the best of the original county court judges. A selection of his early judgments was published between 1850 and 1852. His Lectures, Elementary and Familiar, on English Law (first and second series, 1860–61), written in a popular style, had some reputation in its day.

Francillon died of cholera at Ouchy, near Lausanne in Switzerland, on 3 September 1866. He left, with other children, a son, Robert Edward, also of Gray's Inn, who became a prolific writer, mostly of novels and short stories.