These are Dondorf number 26 patience cards, known as "kinder patience" because the face cards feature children. Because of this, they're quite sought-after, so I was lucky to get them at a price less than the cost of posting them to me. They were manufactured between 1908 and 1920, so are at least a hundred years old. The box isn't in great shape, but the cards themselves are still usable.
The Jack of Clubs looks a bit like a joker. The particular deck I bought doesn't have a joker, but it may have had one originally. The Jack of Clubs is an important card for Dondorf, because the manufacturer's name appears on it (B. Dondorf GmbH, Frankfurt a/M in this period). For British playing cards, the manufacturer's name appears on the Ace of Spades for reasons to do with taxation. This stricture doesn't apply to German playing cards, meaning that they can make the aces more decorative across the board.
I'm quite pleased with these cards, even if they could do with a clean.