It mainly depends on the developer.
Bulgaria and France, India and some in Turkey are staged payments. The theory behind that one is that the builder is supposed to keep the cost down as they can pay off on their own 'mortgage' throughout the build, and that you are only paying for completed work.
Majority in Spain, Portugal and Cyprus are between 10 and 30% down and balance on completion. Mainly to make it more attractive for the buyers. The theory there is that if you only pay 30% down and it takes 2 years to build, it will have gone up in value throughout its build time and therefore worth substantially more upon completion. Or if you want to sell on before completion that you can make a profit on your deposit alone and avoid capital gains tax as your name is not on the title deeds.
Theories only, reality may be a totally different thing. If you are dealing direct with the developer, most will agree terms to suit the buyer as they obviously want the units sold, so a lot could depend on your charm and the character of the developer!