I do apologise Dotty but I am having trouble understanding what you are saying. Please correct me where I am wrong.
You bought an off-plan property from a developer 4 years ago. That property cost you 60.000 R$. You then sold that property after completion this year for 300.000 R$.
Lets take a good look at that. After paying 15% capital gains tax, you will have made net 340% returns on your investment after four years. In other words, your property showed a NET capital appreciation of a staggering 85% per annum.
The same developer is now offering you a comparable property this year which is near completion for 320.000 R$ because they put them up for sale at 320.000 R$ at launch and were unable to shift them.
That doesn't sound anything like property prices crashing, that sounds like an extremely common problem in Brasil which is the developers failure to understand the concept of off-plan investment.
The reasoning behind off-plan sales is that the construction is largely funded by the revenue generated by sales, which enables the developer to spread his own financial resources into more projects than he could initially do on his own. On the other hand, the investor has to be offered a discounted price which warrants putting the money in. The developer can expand their options and the investor gets a property which will increase in value.
What has happened a lot in Brazil and which makes it a challenging market is that the vast majority of the developers don't understand this. The only thing they see is that they sold a property to MX at 60.000 R$ and that MX was able to sell it 4 years later at 300.000 R$. Their argument then becomes "I could have made a lot more money on that instead of the investor" - the next one they do, they price the product out of the market.
In other words, it sounds like the developer got greedy and shot himself in the foot. Once again, classic case of what is happening in Brazil - people offering product at "Gringo" prices. But there are still plenty of developments around which aren't anywhere near the 300.000 R$ mark. In other words, it's time for you to change the developers you work with.
By the way, what was the comparable R$/m2 on that example?