A book I'm reading says; "In the Ottoman Empire, Western European traders former colonies within the city of Constantinople where they were granted commercial privileges" the time period is 17th-18th century. Can anyone give me some more information about this?
If you have the time to read a book to explain part of the book (I know, jokes!) then James Mathers' Pashas: Trades and Travellers in the Islamic World explores the relations between English/British traders with Ottoman authorities, and goes beyond just Constantinople.
There is a lot of material out there: a useful keyword if you want to Google around a little further is the "capitulations" of the Ottoman Empire, they date back a few centuries before than this period (to the Italian trading city-states, Genoa and the like), but the legal/extraterritorial privileges granted to European traders more broadly grew in the 17th and 18th centuries.
The reception of European maritime traders by Mughal India, Qing China and Tokugawa Japan present interesting points of comparison if you're interested in this notion of extraterritoriality more generally.