I bought this at our school Vide Greniers last April. We had decided to have a stall, to clear some clutter and support the school rather than to make much money, although we did make about 40 euros' profit in the end. Across the entranceway from us was a man I took to be a Vide Greniers regular, with a lot of brocante (see post below for translations!)
I'd been across to his stall earlier in the day and admired this strange little thing. I was feeling stingy and wasn't prepared to pay his initial asking price, which was only 5 euros. At the end of the day I went over and offered him 4 euros, which he finally accepted, 'seeing as it's you', he said (we'd been nodding and smiling from stall to stall over the course of the day).
I asked him what it was for, and he and the lady on the stall next door agreed it was to be filled with water for washing: hands or food in the kitchen, I assume, but maybe other things too. Therefore, it's basically a pre-running-water sort of tap. I guess it may have had a little cork in the end so that you could keep water in it all day. The cornflowers are handpainted onto the enamel, and in the summer I had a vase of cornflowers next to it in my kitchen.
When I asked its age he estimated it was from the 1920s. He then rather humbled me by telling me that it had been his mother's, and that he was selling off the contents of her home: was I interested in these charming country-syle chairs? Well, we have lovely chairs ourselves, so I wasn't, but I realised that my assumptions about him being a hard-selling brocanteur were unfair, and I felt quite mean about knocking him down on the price. From what I've seen since I got a real bargain! I've never seen a hand painted one of these again. I think he would be pleased that his mum's posession is so well-treasured again, though.