Is actually a little shop called Harissa in Masarykova street.
I’ve never been to a spice market so I really don’t know what the offer would be like there but I know I was overwhelmed here.
You can pick up any of the jars containing spices and smell them. Everything is listed on the jar,
including one notice that actually warns against opening as it’s the second most hot spice in the world (of course I don’t know the name).
I felt like a kid in a chocolate store. I neither knew where to start reading (let alone smelling) and in the end I just skimmed through everything as the spices weren’t even the reason I was there.
They also have teas, sauces, salts, jars, etc. Well worth the visit if you’re in Zagreb.
P.S. It turns out harissa is actually a spicy paste used in North African cuisine. Sounds just like the thing for me.