A purplish brown shade of red or more specifically pantone 19-1518. Puce was a very popular regency colour and in 1805 The Lady´s Magazine states "The prevailing colours are green, yellow, and puce. Spanish hats of coloured velvet, with feathers to match, are generally worn. Black velvet pelisses, trimmed all round with lace, are most prevalent." It is however thought the colour was made popular in the Summer of 1775 when Louis XVI observed that Marie Antoinette´s brownish dress was "coleur de puce". Puce in French means literally "flea" and so it is the colour of this little blood sucker. The fabric dyers of Marie´s time made distinctions between young and old fleas as well as their different body parts as a means to subdivide and define the various shades of puce.
Buonanni Philippo´s 1681 "Puce"...
...and a portait of Marie from around the time puce was made popular as colour in France.