Iceland will have a Constitutional Assembly “for the purpose of reviewing the Constitution of the Republic.” It will be elected by single transferable vote (STV), in a single national district with a magnitude of 25. The election will be 27 November.
The STV system will include a gender-representation provision:
There is a 40% sex-balance rule that is to be applied after the STV-PR election for the 25 places has been completed. If candidates of either sex do not have at least 10 of the 25 seats (“two-fifths”), additional seats will be allocated to the under-represented sex to bring representation of that sex up to “two-fifths”, subject to a limit of six additional seats. These additional seats would be allocated to the required number of the last eliminated candidates of the under-represented sex.
See more at the Irish Political Reform blog. And thanks to Tom Round for pointing this out in another thread.
Iceland’s M=25 is likely a record for size of an STV constituency.