Basically the rule of thumb is this. Take the average netto income in any country you live and this is what the cost of a flat should be per square meter.
This article may be suitable for kindergarten children but not serious property
property investors, its high time people stopped thinking in terms of zl per square metre, this method was used in the communist times but it has no relevance today. Every property is unique, ie location, type of local structure, and type of neighborhood etc,
You might have two property the same size but prices could be totally different.