Permission for usage of a building – Also known in the practice as “Protocol Act 16”, or “habitation certificate”, it is the final official document in the Bulgarian building process and applicable to every constructed building. It is issued by the National Building Control Department at the Ministry of the Regional Development to certify that the building from 1st, 2nd or 3rd category has been completed in compliance with the Building Law provisions and that it can be legally operated/habitated. It is adbisable to hire an independent Bulgarian conveyancing lawyer to examine and confirm the current legal status of Bulgarian house, apartment, block or villa, before buying it. Only in this way you may avoid a situation where you may buy a property without Occupancy permit (Act 16) and are not able to re-sell it, simply because the next buyer may get a lawyer to ask to check if your property has got Act 16.
See also http://www.bulgariandeals.com/viewtopic.php?f=7&t=80 .
* Note that lawyers do not work for free; their job is paid, so when asking a lawyer for their legal opinion on a concrete legal issue, you should pay them for their opinion and legal advice; it is the same like when you visit a doctor and pay for their competent diagnose and accurate medical treatment.