This is a very nice Chinese polychrome export vase, an antique reproduction piece with Yongzheng marks, but is not of the period. Its likely date is early 20th century.
The form is a traditional "mallet" shape and the decoration is an underglaze blue outline of the design filled in with enamel colors, a palette known as wucai or famille verte. The polychrome colors are laid in by hand, over the glaze, in a subsequent firing. However the palette and the composition of the colors is not quite right to be of the date the marks purport this vase to be.
This is how the colors look on a genuine Yongzheng vase of the period (early 1700s)
and you can see how the hues and saturation are a little different, particularly the rust red. Also, the most telling is that the decorators back then did not have that magenta (rose) color available to them.
The pattern is a nicely designed traditional stylized lotus with associated foliate forms, framed and embellished with red ruyi heads, an auspicious symbol shaped like a lingzhi bracket fungus that confers longevity. Around the neck and shoulder are carnations, the flower of love in the Chinese tradition, again their petals and leaves are stylized in the typical way of the porcelain decorators of Jindezhen.
Around the base is a lappet band of stylized lotus leaves in green, yellow and red.
The mark is an imperial seal for emperor Yongzheng (1723 - 1735) and reads:
Da Qing Yongzheng nian zhi
But it's not of the period for the reasons mentioned.
Here's how to read the marks:
As for value, even though it's a reproduction, this vase would generate some interest at auction and would sell in the range of $200 - $300. It therefore has a full retail or replacement value of $600 and which is what I should insure it for.
I do hope this helps!
Again, apologies for the delay in getting back to you.