In order to stop the so called "drugs tourism", only people that are officially registered as living in The Netherlands are allowed to enter a coffeeshop in Maastricht. And it has been decided that the only allowed way to prove to a coffeeshop that you are registered in the Netherlands is to show them an official piece of paper that is called an "uittreksel uit het bevolkingsregister". This is a signed and stamped statement that basically just says that you are registered in the population register of the Netherlands. You can obtain it at the city hall of the city in which you are registered.
But regardless of whether you want access to a coffeeshop or not, if you want to stay in Maastricht for at least 4 months, you will have to register yourself with the city of Maastricht. And this is regardless of whether you need a residence permit or not. If I (a Dutch national) move to Maastricht or any other city in The Netherlands, I will also need to register in that new city.
For more info on registrering as a student, see https:/…help
Edited: 02 February 2017, 14:24