The key element is to never pay without getting anything in written - and remember that if it seems shady or too good to be true, it probably is. 

You have no legal claim if you haven't received a rental agreement in writing or if you have payed money "under the table". Your rental agreement should state how much the rent is, if there is a deposit and how much, how long you can live there, the terms for giving notice, being asked for moving out, the terms of subletting, the terms of maintenance etc. 

If you experience a scam the organization Lejernes LO http://llo.dk/om-llo/internationalt offers advice and legal counselling to people who have problems with their landlords. They can advice you on your rights and possibilities. 

DO's

  • Check who owns the rental property
  • Always view the rental property
  • Check the rent level
  • Get everything in writing
  • Document any defects when moving in (photos are a good idea)
  • When subletting note what the rules are for the specific subletting deal
  • Make sure that the property is consistent with the rental contract
  • make sure to go through the property
  • Double-check the legality of the arrangement if you are told not to have your postal address there

DONT's

  • Never pay by cash
  • Never pay via a foreign bank account or money transfer service
  • Don't accept landlord pressure
  • Don't be too critical about location
  • Never pay money under the table
  • Don't pay too much in deposit and prepaid rent (ask Lejernes LO, if in doubt)
  • Be aware of non-Danish speaking landlords