Definition of "douce"

The bookseller, douce man, had seen too many eccentric customers to be shocked by the vehemence of his questioner.

1919, Christopher Morley, The Haunted Bookshop‎, New York, N.Y.: Grosset & Dunlap Publishers, page 242

what would you say of a man with plenty of silver that bided all by his lone and made his own bed and did his own baking when he might have had a wife to make him douce and brave?

1932, Lewis Grassic Gibbon, Sunset Song (A Scots Quair), Polygon, published 2006, page 27

If Fabre, for example, were elected to the Academy tomorrow, you would see his lust for social revolution turning overnight into the most douce and debonair conformity.

1992, Hilary Mantel, A Place of Greater Safety, Harper Perennial, published 2007, page 145

So what strong lord of misrule can preside in this douce, commercially respectable, late 19th century city where even religious fanaticism reinforces un adventurous mediocrity?

1996, Alasdair Gray, “The Story of a Recluse”, in Every Short Story 1951-2012, Canongate, published 2012, page 271