The owner of the building, your landlord, or yourself are responsible for the tenants you have in your building. Work without over-site and permitting is a bad thing. I am not sure if a contractor needs to be licensed to get a permit, because even homeowners get permits, but getting the permit and getting the work approved makes it much easier to sell a building, or a condo in that building.
If you have a condo in such a building you should ask for the permits to make sure the work was approved by the city. That is your association's duty, to make sure any rehab in your building is done correctly