Article 62 (2) Organizations of citizens belonging to national minorities, which fail to obtain the number of votes for representation in Parliament, have the right to one Deputy seat each, under the terms of the electoral law. Citizens of a national minority are entitled to be represented by one organization only.

The electoral law of 2000 (PDF) (Chapter 1, Article 4) says that an organisation recognised by the government (a "legally constituted organisation of citizens belonging to a national minority") are entitled to one seat in the Chamber if they (on a nationwide level) manage to receive at least 5% of the average of the votes cast for the election of a single regular deputy. Such seats are thus in addition to the regular number of deputies in the chamber (314). How a specific candidate of said organisation becomes the deputy I'm not sure, but presumably the top vote-getter. The deputies are all, including the minority ones, listed as coming from one of the constituencies.

"The basis of optimism is sheer terror" - Oscar Wilde