Sometimes when I purchase French dinner sets, included will be demitasse cups. They are so tiny at 2" across and about 2.75" tall. Only hold a couple ounces of liquid. So -- what to do with them. I'm not sure there is any beverage I would serve in them. Men certainly could not pick up the cup and drink from it and be comfortable. Most women couldn't either. I do know they were not made to be children's china.
I recently purchased a set of plates that included 10 demitasse cups and saucers intact. It was once a larger royal service evidenced by many saucers with no cups. I purchased the plates mainly because I loved the little crown motif. They have a turquoise border so I will show you them when I do a turquoise tablescape soon.
The crown has seven balls at the top which means it is not a French baron's symbol, but is continental European, such as Austrian or Bavarian/German. I believe you need eight balls on top of the crown to indicate it was made for a French baron and less balls for other royal titles. The cups and plates are not marked which would generally mean Old Paris porcelain, but perhaps not in this case.
The quality of the porcelain certainly indicates that the firm serviced royal families. The monogram is also a sign of that quality. As a china addict, I believe that porcelain "born together" should stay together. Perhaps another owner may have sold off the cups and separated them from the plates, but not me.
So what to do with them. I had them sitting on a console table while decorating for Christmas and just plopped a flameless tealight in one of them. WAH LA, it fit. I placed the lights in all of them to see what it would look like.
The porcelain is thin enough that the light from the tealight comes through. The only thing I don't like about these flameless candles is that they were designed to resemble candlight so are yellow. I prefer the light to be warm white instead. These were purchased a few years ago when they first came on the market. You can now get them in warm white.
I also had a mini garland battery powered light set from Target that I wrapped around the cups for more light in the room. So there is an idea for you.