If you're at the bottom of the stairs that lead to the workshop, look to the left of the line of soldiers and there's another courtyard. The Lucky Well is in there. Examine like you would any other statue.

I followed http://bdotools.com/ amity calculator on this one.. I had 104 amity the first try at 59 interest and 20 favor using this:

Luolo Grebe
Wolfgang
Ashrogue
Psebor
Danielle Stimi
Martha Kiyen
Ario

Place du marché de CALPHEON : fontaine derrière la vendeuse