This depends on whether you are a private individual or a professional vendor:
Every private individual has a once in a lifetime tax free sale option (for a house and land not exceeding approximately 1 donum). If you use this option, you will not be liable to Capital Gains Tax on that sale. On all subsequent sales, Capital Gains Tax will be payable at 3.5%, provided you do not sell more than 3 properties in one year, making you a professional vendor.
For professional vendors, there are no tax exemption rights. Capital Gains Tax is payable on every sale at a rate of 6.25%.