I see what you mean they are very similar but I just found my Davidson no 4 frog and notice immediately the French one doesn't have holes all the way through it would therefore have to be filled with water from the top and wouldn't be placed in a bowl of water as with the Davidson one, the base of the Davidson one is also concave to allow water to circulate under it. The French one only holds the amount of water in each individual pocket and the base is flat apart from tiny feet, the centre hole is much larger the second tier are the same on both frogs and the third tier of the French one is much smaller.