Antiparochi was invented as a way to find housing for Athens's new residents. Antiparochi translates roughly to “mutual exchange.” Here's how it works: The landowner gives a plot of building land to a constructor, who builds an apartment block. In exchange, the landowner receives several apartments in the completed building. This way, constructors could develop projects without having to invest heavily in purchasing plots. Today, these buildings are called “polykatoikia.” If you've been to Athens, you're used to the sight of tall, uniform concrete apartment blocks with uniform balconies, extending as far as the eye can see.
According to Panos Dragonas, professor of Architecture at the University of Patras, there was no specific law that said this transaction could happen. The Greek people themselves thought of it. The government, seeing the many benefits, did not regulate the situation. They only added a few restrictions, like a limit on the height of the apartments and a ban on building over archaeological sites.
The Greek government's idea was to boost construction in order to strengthen the Greek economy. The tax system at the time also favoured new buildings because property transfers (as opposed to new constructions) had a high tax. For contractors, low building costs were ideal because it meant they didn’t need a large loan to start building.