Medieval curfews, also known as “couvre-feu” or fire covers, are ceramic or iron covers used to keep the embers of the fire overnight.
Some extant example of curfews are
The Medieval Household, Daily Living C.1150-C.1450 has some drawings of fragments found of some ceramic curfews, plus some good history and written descriptions.
British Museum has two potential 14th century curfews but no images of either
A French example
No date given except for “lower middle ages”.
A page on the archeology of Villeneuve-d’Ascq says that this is a photo of a 13th century terracotta fire cover.
Seems to have been two styles of curfews – one in which the curfew covered the coals completely and one in which the coals were banked up behind it
15th century, beautifully styled couvre-feu
This 19th century book refers to an early 18th century work in which a curfew has been drawn for reference. Again a half bell, presumably because the fire is being bank in a corner.
a much later example, the V&A has a brass fireguard which is from the 17th century